Majed Eddine Moustaid
email: majededdine.moustaid@supergrid-institute.com

Vincent Platel

Cyril Buttay

STUDY OF CONVECTIVE CONDENSATION IN A THERMOSIPHON LOOP

In this article, we focus on the condenser of a loop thermosiphon designed to cool power electronic component. The objective here is to condense Novec 649, our chosen working fluid for this loop. It is a fluid recently developed by 3M, which is known for having low environmental impact and non-flammable. We first present a theoretical analysis with the calculation and the hypotheses leading to the design of the multi-tubular condenser. Then we present a full size thermosiphon built for experimental validation. A discussion then addresses some of the design hypotheses.

Three main parameters are studied : the tilting angle of the condenser (from horizontal to vertical orientations), the temperature of the coolant and finally the mass flow effect at different saturation temperatures. In our setup, we dissipate up to 2.4 kW at the evaporator level. The produced vapor is then condensed in the heat exchanger using cold water flowing at countercurrent. A number of measurements are made via thermocouples and pressure sensors located at both ends of the condenser to measure the average heat exchange coefficient.

INTRODUCTION

Condensation is an important process that is being found in many industrial applications, such as refrigeration, air conditioning and energy conversion in power plants. Its growth is fueled by the demand for better efficiency especially now that air cooling technologies have reached their limits. For example, regarding power electronics cooling, the miniaturization and densification of electronic components in confined spaces lead to an increase in heat power fluxes that are becoming more and more difficult to extract. Two-phase cooling provides a better and more efficient alternative for future systems.

However, condensation is a very complex phenomena, and although many studies have produced analytical solutions that fit very well in some special conditions, most of the understanding comes from experimental observation through empirical or phenomenological models. This is due to the intrinsic nature of two-phase flows, the interaction and dependency of the liquid and vapor phases on flow conditions, such as angle of inclination, mass flux, temperature, thermo-physical characteristics, all of which affect the efficiency of the condensation process.

NOMENCLATURE A [m 2 ] Section tube area c [m] Tube circumference D [m] Diameter f [-] Friction factor g [m s -2 ] Gravity constant G k [kg m -2 s -1 ] Surface mass flow of phase k H [W m -2 K -1 ] Heat transfer coefficient h LV [J kg -1 ] Latent heat of evaporation j [m s -1 ] Superficial phase velocity J G [-] Dimensionless gaz velocity J T G [-]
Most studies on the matter address horizontal and vertical condensation. Yet, of the few papers which present experimental investigations on inclined condensation [START_REF] Shah | A new flow pattern based general correlation for heat transfer during condensation in horizontal tubes[END_REF][START_REF] Meyer | Condensation heat transfer in smooth inclined tubes for R134a at different saturation temperatures[END_REF][START_REF] Lips | Experimental study of convective condensation in an inclined smooth tube. Part I: Inclination effect on flow pattern and heat transfer coefficient[END_REF][START_REF] Mohseni | Flow pattern visualization and heat transfer characteristics of R-134a during condensation inside a smooth tube with different tube inclinations[END_REF][START_REF] Del Col | Effect of inclination during condensation inside a square cross section minichannel[END_REF][START_REF] Wang | Study on laminar film-wise condensation for vapor flow in an inclined small/mini-diameter tube[END_REF][START_REF] Tepe | Condensation and subcooling inside an inclined tube[END_REF][START_REF] Xing | Froude number dominates condensation heat transfer of R245fa in tubes: effect of inclination angles[END_REF], almost all show that it is much more efficient to condense at tilted angle compared to a purely horizontal or vertical orientation. Thus, the objective will be to check these findings in the frame of a complete thermosiphon, for a specific fluid.

Previous work

Meyer et al. [START_REF] Meyer | Condensation heat transfer in smooth inclined tubes for R134a at different saturation temperatures[END_REF] and Lips and Meyer [START_REF] Lips | Experimental study of convective condensation in an inclined smooth tube. Part I: Inclination effect on flow pattern and heat transfer coefficient[END_REF] studied condensation of R134a with a mass flux ranging from 100 to 300 kg m -2 s -1 . They tilted a 8.34 mm tube between +90 • and -90 • . Maximum heat transfer was found hovering around -15 • and -30 • . The lowest heat transfer was reached for the vertical downward position. It was also found that heat transfer increased with decreasing mass flux.

Mohseni et al. [START_REF] Mohseni | Flow pattern visualization and heat transfer characteristics of R-134a during condensation inside a smooth tube with different tube inclinations[END_REF] also experimented with R-134a. Compared to the previous study, Mohseni made tests with tubes similar to that of Meyer et al. [START_REF] Meyer | Condensation heat transfer in smooth inclined tubes for R134a at different saturation temperatures[END_REF], the angle range was also similar and the mass flux was of the same order of magnitude (from 53 to 170 kg m -2 s -1 ). Yet, the maximum heat transfer was found to be very different from that in the Lips and Meyer study, at +30 • . It should be noted that they both agreed on the minimum heat transfer coefficient at -90 • and that Mohseni made measurement every 30 • while Lips and Meyer made measurement every 15 • . Emiw et al. [START_REF] Ewim | Condensation heat transfer coefficients in an inclined smooth tube at low mass fluxes[END_REF] studied the effect of the temperature difference and inclination angle at low mass fluxes. They used a circular tube and varied the angle between +90 • and -90 • . While temperature difference was not found to have an effect in the upward or the downward vertical position, it was inversely correlated to the heat transfer coefficient regarding downward inclined flow and had no major effect when it came to upward inclined flow.

Del Col et al. [START_REF] Del Col | Effect of inclination during condensation inside a square cross section minichannel[END_REF] used R-134a and R-32 in their experiments. However, they used a square channel of an equivalent hydraulic diameter of 1.23 mm. The inclination angle was also varied between +90 • and -90 • . The major findings being that heat transfer decreased with inclination below a certain mass flow rate threshold. They produced a numerical method to predict and calculate this threshold value.

Lyulin et al. [START_REF] Lyulin | Experimental study of laminar convective condensation of pure vapor inside an inclined circular tube[END_REF] studied the condensation of ethanol in a 4.8 mm circular tube, with a laminar flow. At 58 • C and with a mass flux ranging from 0.24 and 2.04 kg m -2 s -1 they found that the heat transfer coefficient was maximum between -15 • and -35 • , and that the heat transfer was inversely correlated to the temperature difference between the vapor and the cold source.

Wang and Du [START_REF] Wang | Study on laminar film-wise condensation for vapor flow in an inclined small/mini-diameter tube[END_REF] condensed water in 4 tubes with diameters of 1.94, 2.8, 3.95, and 4.98 mm. The inclination angles ranged from 0 • to -45 • . They found that tube diameter affected largely the efficiency of the condensation. Heat transfer coefficient was maximum at 45 • in larger tubes and minimum in the smaller ones.

Tepe and Mueller [START_REF] Tepe | Condensation and subcooling inside an inclined tube[END_REF] experimented with methanol. Inclinations were limited to three values (0 • , -15 • and -90 • ). At low heat flux, maximum heat transfer was also found at -15 • . Minimum heat transfer was found at the downward vertical position.

Finally, Xing et al. [START_REF] Xing | Froude number dominates condensation heat transfer of R245fa in tubes: effect of inclination angles[END_REF] condensed R134a with a mass flux ranging from 199 to 699 kg m -2 s -1 . They tilted a 14.81 mm diameter tube between +90 • and -90 • . Maximum heat transfer was found at both -15 • and +30 • . The effect of the inclination angle was also found to increase with decreasing mass flux. Based on the Froude number, they produced a formula that can calculate the variation of the heat transfer coefficient with the inclination angle, knowing its value in the horizontal position.

Application case

The design and making of the thermosiphon loop is part of a larger project in power electronics. Converters are designed to handle up to 800 kW of electric power each. They are based on inverter structures which can dissipate up to 8 kW of heat. Each inverter is made up of two half-bridge structures that can dissipate 4 kW each. The thermosiphon is evaluated as a replacement for the current water cooling system. Some key aspects of the half bridge structures are summarized below.

Efficiency of "half-bridge" (worst case): 99 % (98 %) Power to be dissipated (worst case): 1.8 kW (4 kW) Baseplate setpoint temperature : 70

• C heat flux (worst case): 4.3 W cm -2 (9 W cm -2 )
2 Design of the condenser 2.1 Two-phase flow configuration

The condenser will be subject to a two-phase flow. The behavior of both phases and their interfaces can take multiple forms, depending on flow conditions. The main way to identify patterns still rely on "flow maps". Overall, seven main flow patterns have been identified. They are indexed in "flow maps" such as the example given in Figure 1. They have been developed by observing the vapor and liquid flow distribution in a purely experimental approach, using common fluids and small tubes. They are used to characterize the transition regions between flow patterns and to get an idea about the flow pattern before any attempt of making an analytical model. The flow maps use logarithmic scales and either use dimensionless coordinates or the superficial flow velocity j k for each phase defined as:

j k = Qv k A = G k ρ k (1)
where :

G l = G(1 -x) and G v = Gx
In our case, the condenser is cooled using water in a countercurrent flow system. With our chosen multi-tubular condenser structure, two main design parameters are to be defined: the number of tubes and the internal diameter of each one. The length of the condenser L is arbitrarily set at 1 m. We assume that the vapor flow is equally distributed among all tubes in a permanent flow hypothesis. Regarding the internal diameter, 5 common values are evaluated: 12, 16, 18, 20 and 30 mm. For each of them, we calculate both liquid and vapor superficial velocities (eq. 1) in order to guess the flow pattern. The use of a map made for air\water flow to predict a two phase flow of a new refrigerant is due to lack of such maps for refrigerants. The next step is to solve the equations of conservation of mass, momentum and energy. This will allow us to calculate the maximum condensed power per tube and thus the number of tubes required in the condenser. The results being angle-dependent, we will focus the theoretical developments in this paper to the horizontal position (only for simplification purposes). We will use a two-fluid system since it is expected to have a stratified flow. The goal here is to primarily calculate the void and mass fraction . The equations of conservation are written as follows:

dρ v αU v dz = Ṁl (2) dρ l (1 -α)U l dz = -Ṁl (3) dρ l (1 -α)U 2 l dz = -(1 -α) dP dz + τ il li A + τ pl c pl A + ρ l (1 -α)g sin θ -Ṁl U l (4) dρ v αU 2 v dz = -α dP dz + τ iv li A + τ pv c pv A + ρ v αg sin θ + dotM l U l (5) ∂ [ρ v αH v U v + ρ l (1 -α)H l U l ] ∂z = GhLV dx dz = - Qp S p A ( 6
)
We use equation 3 and 2 to eliminate the pressure gradient, this will give us a void fraction equation to solve :

dα dz G 2 x 2 (1 -α) ρ v α 2 + (1 -x) 2 α ρ l (1 -α) 2 = dx dz G 2 x(1 -α) ρ v α + (1 -x)α ρ l (1 -α) -α(1 -α)(ρ l -ρ v )g sin θ + (1 -α) τ pv c pv A + α τ pl c pl A - τ iv li A ( 7
)
Heat is being transferred from condensing NOVEC649 vapor to the water coolant through internal tubes made from stainless steel. Dissipated heat can be calculated as follows :

Qp = ∆T L 1 H φ πD int + 1 H water πD ext + log D ext D int 2πλ SS (8)
For the outer flow of the water coolant, we use the Gnielinski [START_REF] Gnielinski | New equations for heat and mass transfer in the turbulent flow in pipes and channels[END_REF] correlation. As for the inner two phase flow condensation, we will use the heat transfer set proposed by Cavallini et al. [START_REF] Cavallini | Condensation in horizontal smooth tubes: a new heat transfer model for heat exchanger design[END_REF]. The set of equations defined in the paper and needed to calculate heat transfer are defined as follows :

if J G ≤ J T G , H φ = H D else H φ = H Annular
with the following definitions :

J G and J T G are two dimensionless parameters defined in [START_REF] Cavallini | Condensation in horizontal smooth tubes: a new heat transfer model for heat exchanger design[END_REF] as :

J G = xG (gDρ V (ρ L -ρ V )) 0.5 J T G = 7.5 (4.3χ 1.111 tt +1) -3 +C -3 T -1 3
Where C T = 2.6. It should be noted that this value is given for refrigerants like CFC's, HCFC's and HFC's . NOVEC649, being an HFO and a new fluid on the market, some caution should be taken upon the calculated results.

H Annular = 0.023Pr 0.4 l Re 0.8

LO

x(1α)

ρ v α + (1 -x)α ρ l (1 -α) 1 + 1.128x 0.817 ρ l ρ v 0.3685 µ l µ v 0.2363 1 - µ v µ l 2.
144

Pr -0.1 l (9)
H Strat = 0.725 1 + 0.741 1 -x x 0.3321 -1 λ 3 l ρ L (ρ l -ρ v )gh LV µ l D∆T 0.25 + (1 -x 0.087 )0.023Pr 0.4 l Re 0.8 LO λ l D (10)
H D = H Annular J T G J G 0.8 -H Strat J G J T G + H Strat (11)
Finally the Lockhart Martinelli coefficient is calculated as [START_REF] Cavallini | Condensation in horizontal smooth tubes: a new heat transfer model for heat exchanger design[END_REF]

χ tt = 1 -x x 0.9 ρ V ρ L 0.5 µ L µ V 0.1

Numerical Results

The goal was to determine the minimal number of tubes that would allow to condense all the vapor coming from the evaporator. The maximum coolant temperature is set to 313 K, while the maximum saturation temperature of NOVEC649 when dissipating 1.8 kW is set at 323 K which gives us a maximum of 10 • C temperature difference upon condensation. Finally, Thermodynamic data relative to NOVEC649 were acquired thanks to the NIST REFPROP 10.0 Database. Figure 3 gives an example of solving the void fraction equation over the 12 mm tube diameter, compared to the Lockhart-Martinelli correlation for void fraction [START_REF] Lockhart | Proposed correlation of data for isothermal twophase, two component flow in pipes[END_REF]. The difference does not exceed 5 % in absolute value.

Figure 4 shows the minimum number of tubes required, as a function of their diameter. As expected, the diameter is inversely correlated with the number of tubes. Figure 5 shows the volume taken by the condenser, also considering the volume of the water coolant. Here, the volume is directly correlated with the diameter and the smallest condenser is the one with the smallest diameter. Combining the two criteria, we choose the condenser with the smallest tube diameter (12 mm) to be built.

Early experimental results

In our thermosiphon loop, the criteria used to evaluate the efficiency of the condenser is the temperature difference between the outlet of the condenser and the outlet of the water coolant. A smaller value translates to a high heat transfer coefficient and thus a more efficient condensation. We measure this value in a permanent state defined by the stabilization of temperatures for 30 min within the margin of error which are 0.2 • C for our T type thermocouple. For each angle of inclination, we dissipate from 300 W to 2.4 kW in our evaporator. The corresponding vapor

Angle and mass flow effect

The figure 6 shows the temperature difference measured for different angles and different mass flows. The figure clearly show that raising the mass flow through dissipating more power in the system raises the temperature difference needed to condense the fluid for all angles. As more mass flow is passing through the tubes, the flow is more turbulent and the exchange is enhanced but the energy being dissipated also raises which explains the increase in the temperature difference.

As for the inclination effect, the angle that were tested are 0 • , 15 • , 30 • , 45 • , 60 • and 90 • in the downward flow position. Analysing figure 6 shows that the inclination has no effect at laminar flow (up to 600 W dissipated), as we raise the power and thus the mass flux, the inclination effect comes into play as the vertical position has the most temperature difference and thus the worst dissipation rate compared to other angles. With a difference of 1.8 • C compared to the horizontal position when dissipating 2.4 kW. This corresponds to almost 20 % increase

Conclusion

We have made a loop thermosiphon as part of a solution used to cool down electronics, we are currently studying all aspects of the loop. This paper focuses only on the condenser and the condensation process. We have showed here the calculation that have been made as a first step to get an idea about the dimensions in order to make the condenser. Figure 7 shows the condenser that's been made for the tests, NOVEC649 coming from the evaporator is condensed and the heat is dissipated by the counter-current external flow of water. Analysing the first results, we have seen that increasing mass flow increases the temperature difference needed for the process. the effect of inclination increase with mass flux and the worst angle corresponds to the vertical position. This result constitute the early measured results for this test bench. More tests will be done to verify these observations.

Figure 1 .

 1 Figure1. Air/water flow map in a horizontal tube[START_REF] Mandhane | A flow pattern map for gas-liquid flow in horizontal pipes[END_REF]

Figure 2 .

 2 Figure 2. Superficial velocities indicating that flow will be stratified predicts a stratified flow for the horizontal position for all chosen diameters.The next step is to solve the equations of conservation of mass, momentum and energy. This will allow us to calculate the maximum condensed power per tube and thus the number of tubes required in the condenser. The results being angle-dependent, we will focus the theoretical developments in this paper to the horizontal position (only for simplification purposes). We will use a two-fluid system since it is expected to have a stratified flow. The goal here is to primarily calculate the void and mass fraction . The equations of conservation are written as follows:

Figure 3 .

 3 Figure 3. Comparison of the void fraction as a function of mass as predicted by the Lockhart-Martinelli correlation and as calculated with the numerical model.

Figure 4 .

 4 Figure 4. Number of necessary tube to have a complete condensation

Figure 5 .

 5 Figure 5. Total volume of the internal condenser tubes Mass flux g/s G per tube kg/m 2 /s Inlet vapor Re

Figure 6 .

 6 Figure 6. Temperature difference between the outlets of the fluid and the coolant as function of angle of inclination for different dissipated powers in the system. compared from the minimum.

  2 /s Inlet vapor Re

	300	3,33	1,55	795
	600	6,67	3,1	1591
	900	10	4,65	2387
	1200 13,34	6,21	3183
	1500 16,68	7,76	3979
	1800 20	9,31	4775
	2100 23,35	10,86	5570
	2400 26,7	12,42	6388
	mass flow for each case is listed in the table below. These values
	were calculated based on the thermodynamic properties of the
	fluid :


Morten Misfeldt
email: misfeldt@learning.aau.dk

Attila Szabo
email: attila.szabo@stockholm.se

Ola Helenius
email: ola.helenius@ncm.gu.se

Surveying teachers' conception of programming as a mathematics topic following the implementation of a new mathematics curriculum

Keywords: Programming, mathematics, computational thinking, curricular changes

In this paper, we investigate mathematics teachers' conception of the relationship between mathematics and programming. The context of the investigation is a recent curriculum reform in Sweden that makes programming a compulsory element of the national mathematics standards. Following up on an in-service training initiative, we conducted a pilot survey (N = 133) exploringamong other thingsthe teachers' conception of the relationship between mathematics and programming. The results suggest that the teachers, on average, feel that there is a strong, but not very strong, relationship between the two subjects. Furthermore, the results suggest that mathematics teachers are interested in working with programming but that they do not feel well prepared for taking on that task. These results are used to discuss the mathematical potential of the different ways in which compulsory programming can be introduced in schools.

Introduction: Programming as a new element in compulsory school

Programming, computing, computational thinking [START_REF] Wing | Computational thinking[END_REF], technology as a subject, and similar topic formulations are currently being included in the curriculum of compulsory schools in many countries. The purpose of these changes is ostensibly to support students in becoming technologically literate and able to participate in the society of the future, as well as to promote STEM careers. Different countries are taking different routes to implement this change. In Great Britain, the main idea has been to develop a computer science curriculum as a new topic, whereas other countries such as France, programming is included in the mathematics curriculum. European approaches to computing in schools differs [START_REF] Vahrenhold | Informatics Education in Europe: Are We All in the Same Boat[END_REF] but most countries have technological skills and literacy as increasingly important objectives of K-12 teaching students, and they share the challenge of building the necessary teacher capacity [START_REF] Wilson | Running on empty: The failure to teach K-12 computer science in the digital age[END_REF].

The specific relationship between mathematics and programming have been explored by scholars such as [START_REF] Papert | Mindstorms: children, computers, and powerful ideas[END_REF] and [START_REF] Dubinsky | The Concept of function: aspects of epistemology and pedagogy[END_REF] and we know that the potential for learning mathematics through programming depends on a number of other contextual factors (Misfeldt & Ejsing-Dunn, 2015). Investigations of the relation between programming and mathematics, have typically taken aim at the potential of using programming as a vehicle for developing mathematical competence. The current situation is almost the converse; programming is included in the national curricula and standards and mathematics, is in some cases used as a vehicle to meet that goal.

In Sweden programming became a compulsory part of mathematics (and science) in autumn 2018. Therefore, several in-service activities have been developed and were already started in spring 2018 and all three authors of this paper have been involved in the development. As part of this work, we decided to conduct a survey of how Swedish mathematics teachers have experienced the introduction of programming as a topic in their teaching. This paper is our first report on the data from this survey1 , and we will continue by describing the Swedish situation and then go on to the theoretical understanding that underpins our work, as well as our method. In the last part of the paper, we present descriptive statistics on the teacher's conception of the relationship between mathematics and programming in his/her class. We end the paper by discussing how to implement programming in relation to mathematics in light of the presented results.

An in-service professional development program in Sweden

The structure of the Swedish national curricula of both primary and secondary mathematics (grades 1-9) as well as upper secondary school builds on certain special "central content," such as algebra, numbers, statistics, and geometry as well as five to seven competencies (e.g. problem solving, reasoning and communication). The grading criteria mostly relate to these competencies. Programming has been included in school mathematics through the revision of the curricula, in which it is referred to in connection with the specified central content.

The Swedish National Agency of Education is responsible for the implementation of programming in grades 1-12, while Swedish schools are governed by municipalities, companies, or nonprofit organizations. The National Agency has arranged courses in programming for teachers. These courses are not related to mathematics teaching but are simply oriented towards developing the teachers' own programming competency. To attend to the didactical question of how to include programming in mathematics teaching, the National Agency also decided that specific professional development (PD) modules should be designed2 .

The context for the creation of these modules is that Sweden has recently carried out a large-scale PD program involving all teachers of mathematics in grades 1-9 and in upper secondary school. [START_REF] Boesen | National-scale professional development in Sweden: theory, policy, practice[END_REF], describes the program and effect and Lindvall, Helenius and Wiberg (2018) describes the program theory that was used in the initial design. Briefly, the program consists of several different PD modules that teachers may choose among. These modules were designed by researchers and teacher educators. Each part of the module follows a cycle in which teachers first study the PD material individually (60 minutes per part), then meet in groups and discuss the PD material and plan lessons together (90 minutes), after which they carry out those lessons with their regular classes (one lesson), and then again discuss the material and the lessons (60 minutes). Schools are monetarily compensated for teachers to attend two such modules, but the modules are free to use for teachers or schools that want to do more PD. As support for the implementation of programming in school mathematics, the National Agency decided that a special programming module should be designed. The first and third author of this paper were part of the design team. We describe the conceptual framework underlying this module below, but one interesting difficulty was that the level of programming competency among teachers was unknown. From reviewing teacher education, based simply on our background knowledge of Swedish teachers, we knew that their programming knowledge and experience were probably rather basic and probably lower the earlier in the school system that the teachers taught. However, at the time, the time frame available for the design of the module did not allow more research into this question. The future effects of such a large-scale programming reform will be interesting to follow up, and as an aid to better understand such effects, we carried out a survey among 133 teachers. The intent of this survey was to establish a knowledge base for understanding the situation among teachers now and to form a basis for further longitudinal investigations. The present paper describes the design of this survey by relating it to some of the ideas we developed when constructing the PD module and presents some preliminary survey results.

Conceptual framework and ideas about the relationship between programming and mathematics

When designing the PD module, a view of mathematics that we found helpful was the Piagetianbased work by Vergnaud, in particular his work on representations (1998). Briefly, mathematical ideas (concepts, theorems, etc.) are, on one hand, related to situations where some particular mathematics makes sense and, on the other hand, related to representations, such as language or other semiotic systems used to signify mathematical matters. Vergnaud's reasoning can be extended to programming, but here, situational phenomena are instead represented in terms of programming code. A real-world situation hence can be modelled either by programming code or by mathematical concepts. Moreover, for understanding, analyzing, or improving the code, it may often make sense to use mathematics, and conversely, if a mathematical model of a situation already exists, that can often be translated into code. This creates an interesting and quite complex dynamic among real-world situations, the world of code and the world of mathematics. This prompted us to consider two different programming situations in relation to mathematics. Type 1 is where the programming concerns some concrete phenomenonto take a classic example, a model of a turtle moving in some particular pattern. For type 1, mathematics is not necessarily a part of the modelling of, for example, the turtle's movements. This modelling can be done purely in programming code. Therefore, for mathematics lessons based on type 1 programming, the teacher must assume the responsibility of extracting or inserting mathematics into the lesson. Using the work of Misfeldt and Ejsing-Dunn (2015) on programming and mathematics, we described three intersecting points or potentials: (1) viewing students as producers of code; (2) supporting abstract thinking; and (3) developing algorithmic thinking. Awareness of such potentials could, we hypothesized, assist teachers when helping students to mathematize their work in type 1 situations.

The type 2 situation, is when the programming part concerns something that is already mathematical, as in using programming to build a mathematical tool, solve a mathematical problem, or to explore mathematical phenomena. In type 2 situations, the mathematics is already relatively fixed, but an important responsibility of the teacher, particularly when working with pupils who are programming novices, is to make sure that the pupils are properly introduced to elements of programing that can be useful in approaching the mathematical problem at hand [START_REF] Guin | Mastering by the teacher of the instrumental genesis in CAS environments: necessity of instrumental orchestrations[END_REF].

In order to investigate the teachers' ideas about the relation between mathematics and programming empirically, we have chosen to focus on how the teachers conceptualize this relation. We use the notion of conceptions to signify what the teachers think are important aspects of the relation between the two areas of knowledge. Our construct of conception is built upon the same constructivist post Piagetian approaches as our mathematics education approaches [START_REF] Papert | Mindstorms: children, computers, and powerful ideas[END_REF][START_REF] Vergnaud | A comprehensive theory of representation for mathematics education[END_REF], and as a consequence, active articulation and representation of the relation between the mathematics and programming plays a critical role in shaping individual conceptions. We explore the conceptions through questions focusing on importance of the relation, preparedness of the teachers to teach programming and the qualities of the relations between the two topics, based in the three intersection points from Misfeldt and Ejsing-Dunn (2015).

Methods and instruments

To understand how the change in curriculum and the work in the PD modules are experienced by Swedish mathematics teachers, we designed a survey addressing various aspects of these issues.

Participants

The participants were teachers from school years 1-12 in municipal schools in Stockholm. Some months before the study, the participants attended seminars organized by the Education Administration that aimed to facilitate the introduction of programming into school mathematics. Prior to these seminars, the participantsas well as the vast majority of Swedish mathematics teachershad no formal education in and very little experience in programming. When attending the seminars, teachers submitted their email addresses, and these addresses were subsequently used to contact them about the survey. Answering the survey was optional, and the teachers were guaranteed anonymity. After the responses were gathered, the teachers who responded received the opportunity to participate in the present study. They were informed that their answers and personal data would be stored according to the current GDPR regulations. Currently, 133 teachers have chosen to participate in the study, 77% (102 teachers) from primary school and 23% (31 teachers) from upper secondary schoolhowever, not all teachers answered every question of the survey.

The survey

The survey was developed by the authors of this paper; the included statements are based on the revision of the Swedish curricula with regard to programming in mathematics, on feedback from teachers at seminars about introducing programming, and on authors' experience of designing PD programs for mathematics teachers. The statements deal with 17 topics, representing the categories: a) teachers' prior experiences of teaching mathematics and programming; b) teachers' conceptions of how programming should be implemented in mathematics; c) teachers' conceptions of how programming could develop pupils' understanding of mathematical concepts and procedures, and pupils' problem-solving competency. In order to achieve an appropriate level of reliability and validity of the responses (expected to be above 100)in concordance with studies about survey scales in social sciences, that point out that the "optimum number of alternatives is between four and seven" [START_REF] Lozano | Effect of the number of response categories on the reliability and validity of rating scales[END_REF] we decided to use a four-alternative Likert scale. By using an even scale, i.e., a scale without a neutral middle categoryand by taking into consideration that the participants had little or no previous experience of programmingwe aimed to discern participants' responses in more distinct ways. Thus, participants were asked to answer to every statement on a scale of 1 (meaning "not at all") to 4 (meaning "to a great extent").

The survey underwent a substantial a priori testing with a group of teachers with similar levels of experience in programming in mathematics as the participants, thereby confirming that included statements were compatible with the aims of this study. In this paper, we are focusing teachers' answers to 12 statementsdisplayed at the next sectionrelated to mathematical thinking and mathematics as a topic and a set of learning objectives on one side, and programming activities and objectives on the other. The first eight statements focus on teachers and pupils' mathematical knowledge and potential related to programming, and on their understanding of mathematical concepts, procedures and algorithms in the context of programming. The last four statements deal with teachers' enthusiasm and preparations related to programming, their views on programming and mathematics as different subjects and on learning programing by tinkering.

Results

We performed a simple descriptive analysis in this paper, thus, the paper does not present or confirm any hypotheses. Rather, we generated an overview of the replies and present our questions and their relationship to the framework.

In the survey, we gathered data about a number of things as described above. We asked the eight questions shown in Table 1, and the distributions of the answers were more or less the same.

Question

Not at all 2 3

To a great extent I benefit from my mathematical knowledge when I am programming.

8 32 59 32 My pupils benefit from their mathematical knowledge when they are programming. 7 36 57 28 I can do more things related to mathematics when using programming.

12 34 60 22 My pupils can do more things related to mathematics when using programming.

11 39 62 15 I can obtain a better understanding of mathematical concepts by using programming. 20 43 48 14 My pupils can obtain a better understanding of mathematical concepts by using programming.

19 33 57 16 I can obtain a better understanding of mathematical procedures and algorithms by using programming.

15 33 54 27 My pupils can obtain a better understanding of mathematical procedures and algorithms by using programming. 9 26 64 29

Table 1: The distribution of the number of answers to respective questions about the relationship between programming and mathematics.

As seen in Table 1, the most typical answer was category 3. The answers to every question have more or less the same distribution; almost half of the teachers answered 3 and less than one fifth of them answered 4 ("to a great extent"). The rest of the teachers, less than one third of them, were divided between 1 ("not at all") and 2 (that might be interpreted as "to a small extent").

Do you feel enthusiastic about teaching programming in mathematics? 23 29 55 23 Do you feel well prepared to teach programming in mathematics? 40 42 43 6 Programming and mathematics are two different disciplines that should not be taught within the same subject.

52 38 24 18 It is important that students learn to modify and adapt given programs according to certain criteria (tinkering).

12 29 64 20

Table 2: The distribution of the number of answers associated to respective statements about teachers' motivation for and self-esteem regarding teaching programming in their mathematics classes.

According to Table 2, the answers associated to the teachers' levels of preparation to teach programming in mathematics respectively to their opinion about the relationship between programming and mathematics as disciplines, are distributed towards less affirmative categories.

All together, we take the results shown in Table 1 and Table 2 as signs of two issues that both need further statistical inquiry in order to be considered stable results: (1) Swedish mathematics teachers do see a clear relationship between mathematics and programminghowever, this does not mean, that the teachers view these topics as coinciding;

(2) despite admitting the benefits of programming, Swedish mathematics teachers are not well prepared for teaching programming in mathematics. Rather, the teachers express that they and their students can use their mathematical competencies while programing and feel that it is a good idea to do this. Yet, simultaneously, they do not currently feel well prepared to take on the task of teaching programming. In the following section, we will discuss these results.

Discussion: approaches to including programming in compulsory schools

Many countries, municipalities, and schools are currently struggling with how to introduce programming as a body of knowledge in the school system. Mathematics tends to play an important role in a number of these attempts. There are many ways in which this can be done in terms of curriculum structure. Programming can be included in mathematics and science curricula, as in the case we have explored here. Of course, this can also be done in different ways, and different teachers will have different competencies in this regard. Another approach is to develop programming as a topic in its own right. However, such a topic can have different "flavors" and foci and different relationships to the more traditional school topics. The Swedish case is an example of a country addressing this problem by imbedding programming into mathematics (and science), and the data from our case suggest that there are a number of synergies and potentials with such an approach. In general, the teachers who answered our survey do see a relationship between programming and mathematics, and they do want to build on that relationship in their teaching. This tells us that the route of integrating programming into mathematics seems feasible in Sweden. However, we should be aware of the fact that both the sample size and current sampling strategy challenge the generalizability of the results. Accordingly, these results say nothing about whether combining mathematics and programming is the best way to address the integration of programming in Swedish schools or even if this integration is a good idea in the first place. Yet, the relationship between the topics and the motivation for taking on the task seems to be there, even though the capacity for teaching programming is not yet in place. We are not free from the problem of training teachers to take on this specific task.

The introduction of programming in the mathematics curriculum poses an interesting implementation problem. What are the critical choices and concerns that we need to consider in this respect? In this paper, we have addressed mathematics teachers' conception of the relationship between mathematics and programming, but this is not the only relevant concern. Stakeholders such as end users (pupils and teachers), implementation plans, the potential for diffusion, etc., are important concerns. We also believe that the discussion of whether to teach programming in relation to other topics or as a topic in its own right could benefit from a broader "implementation framework," such as the one discussed by [START_REF] Century | Implementation research: Finding common ground on what, how, why, where, and who[END_REF]. To mention just one concern, it is critical to have sound implementation of programming in relation to mathematics education, and that could benefit from being viewed through the lens of implementation research; we can look at teacher's resistance to programming as part of mathematics. This resistance is rare but might exist, as seen in Table 2. If programming is included as a part of mathematics at all levels, no mathematics teachers can avoid teaching it. Accordingly, programmingthat is, not a priori natural tool for mathematics educationmight also be viewed in the light of instrumental distance and double professional geneses from the part of the teachers (Haskepian, 2014). In that sense, this structure is more fragile for the minority with negative views, whereas the development of an entirely new topic might make it easier for teachers to choose whether they want to engage in the teaching of programming.

Conclusion

In this paper, we have presented an initial descriptive analysis of Swedish mathematics teachers' experience regarding the relationship between mathematics and programming. The data collection is still ongoing, and the sample size is expected to increase. Furthermore, we are not yet in a situation where we can conduct a strong statistical analysis of the data, so the stability and generalizability of the results are currently limited. However, the results that we do have point in the direction of a meaningful relationship between mathematics and programming that can be used to support the teaching of programming within the subject. Yet, they also suggest that this will not be easy and that Swedish teachersdespite a positive attitude towards working with programming in mathematicsdo not feel that they are prepared to take on this task. This result indicates that it might be a good idea to build the capacity for teaching programming from within the topic of mathematics. However, the capacity problem seems to persist in the sense that it is indicated that teachers need to be prepared and trained to teach programming. Furthermore, it might be the case that some teachers do not at all see the relationship between mathematics and programming, nor the relevance of teaching programming in their mathematics classes, and such teachers might also experience the task as very challenging. However, we assume that further data collection and statistical analysis will allow us to better understand the detailed clustering of teachers' attitudes on the subject of programming.

Since the data collection is ongoing, this paper can be regarded as a pilot study. More results and insights will be explored further in the continuing work.

The digital material supporting the professional development program can be found here: https://larportalen.skolverket.se/#/moduler/0-digitalisering/alla/alla


What sign languages teach us about bilingualism Evangelia Adamou

French National Centre for Scientific Research (CNRS), Oral Tradition Languages and Civilizations laboratory (LACITO)

There is currently a boom in research on sign languages contributing not only to a better understanding of how sign languages work but also to a variety of theoretical discussions in linguistics. Indeed, sign languages present several specificities that allow researchers to take a fresh look at a number of research questions, old and new alike. For example, sign languages are generally new languages -most of them with less than 200 years of use-and as such offer a privileged look into language creation which was addressed mainly through the study of Creoles and Pidgins. In particular, the study of homesign languages -created by children who do not have access to any input-gives us the rare opportunity to observe the fundamentals of human language [START_REF] Goldin-Meadow | The resilience of structure built around the predicate: Homesign gesture systems in Turkish and American deaf children[END_REF]. Sign languages are also of special interest because they rely on the manual modality and therefore offer a window onto cognition, beyond what can be observed through the study of co-speech gesture. Also, bilingualism involving sign languages is another fascinating aspect that has recently been the focus of attention and is discussed in several articles in the present volume.

As summarized in [START_REF] Zeshan | Two languages at hand: Code-switching in bilingual deaf signers[END_REF], three lines of research can be identified for bilingualism involving a sign language (see Table 1): a) Research on sign bilingualism, targeting the study of bilinguals who use in parallel a sign language A and a spoken language B in its written form.

b) Research on bimodal bilingualism, examining the hearing individuals who use a sign language A and a spoken language B. c) Research on sign multilingualism, considering the bilinguals who use more than one sign languages. The articles in this volume focus on two of the above-mentioned types of bilingualism, i.e., bimodal bilingualism and sign multilingualism.

Bimodal bilinguals use in parallel a sign language, which relies on manual and nonmanual (facial) signs, and a spoken language. Studies on bimodal bilinguals therefore allow us to observe the simultaneous articulation of two languages, a co-articulation which is impossible for spoken languages as they both unfold in the same modality. Interestingly, the sequential use of a sign language and a spoken language, similar to codeswitching observed in spoken languages, is rare. The two ways of language mixing, simultaneously or consequently, therefore seem to largely depend on language modality. According to [START_REF] Emmorey | Bimodal bilingualism[END_REF], the fact that bimodal bilinguals prefer using both languages rather than suppress one of them indicates that this inhibition mechanism is associated to high cognitive costs.

Researchers note that the parallel use of a sign language and a spoken language develops naturally among hearing children of deaf parents.1 Studies show that, despite inter-speaker variation, the spoken language is generally dominant in bimodal bilingual communication (also see Müller de Quadros, Lillo-Martin, and Chen Pichler, this volume). The interpretation of this finding is still under debate with some researchers considering that it is due to the fact that spoken languages are dominant in the broader sociolinguistic context, others suggesting that this preference may be reflecting a more general human preference for spoken language [START_REF] Lillo-Martin | Language choice in bimodal bilingual development[END_REF], and others yet indicating that the focus is likely to depend on the communicative setting (Zeshan and Panda 2017 mention that the bimodal individual may adopt different styles depending on her primary and secondary audiences).

Bimodal bilingual communication should be differentiated from what is termed Simultaneous Communication, a form of bimodal communication which is used in formal settings, such as meetings and lectures, and which explicitly targets the parallel use of sign and spoken languages. Bimodal bilinguals, in contrast, do not explicitly aim at the use of the two languages, but this co-articulation arises spontaneously and often becomes the default mode of communication. This clearly indicates that both languages are active for the bimodal bilinguals, thus supporting results from unimodal bilingual studies which indicate that both languages are "on" among bilinguals. Similar to the well-documented capacity of bilinguals to choose the appropriate code since an early age, the present studies also demonstrate that bimodal bilinguals are sensitive to the communicative context and to their interlocutors and can suppress one of the two languages when appropriate.

A widely-used method for the study of bimodal bilingualism is the corpus-based analysis of semi-spontaneous interactions and this is the method that prevails in the studies of this volume. Corpus-driven research of naturalistic communication is a popular method for the study of bilingualism in general although grammaticality judgments and experimental research are equally widespread for spoken languages. However, this does not seem to be the preferred option for the study of sign languages even though some experimental research is being conducted. The privileged use of corpora for the study of bimodal bilingualism might be due to the fact that sign languages are not yet well described, bringing the methodological concerns closer to those that dominate more generally the study of lesser-described languages.

Analysis of a variety of naturalistic corpora, in general and in this volume in particular, indicates that bimodal bilinguals do not continuously use jointly the two languages, i.e., the spoken language and the sign language. This may be due to restrictions related to the cognitive load involved in the use of two languages in a single interaction, much like what has been experimentally shown for spoken language alternation. However, I would like to suggest that the systematic use of a sign language and a spoken language in daily communication, as practiced by highly proficient bilinguals, most likely attenuates processing costs as demonstrated in a study involving bilingual speakers that frequently codeswitch in everyday life (Adamou and Shen 2017). Moreover, constant parallel use of the sign and spoken language is attested in Simultaneous Communication among trained individuals who develop this specific skill (see "A community profile of "sign-speakers" at the Indore Deaf Bilingual Academy" this volume), similar to what has been reported for professional interpreters who demonstrate greater cognitive ease with language alternations [START_REF] Ibáñez | Language access and language selection in professional translators[END_REF]. Memory and processing limitations could therefore be considered as biases, but not necessarily as the triggering factors for this bilingual behaviour.

Since parallel use of a sign language and a spoken language is partial, the contexts in which such parallel use does occur are of great interest for linguists. For example, while most studies show that there is generally semantic congruence between the sign and the spoken language, i.e., same meaning expressed in the signed and spoken components, it appears that structural congruence is not required. Again, when comparing with the literature on codeswitching, recent studies show that although structural congruence is a facilitating factor, it is definitely not a prerequisite for codeswitching [START_REF] Torres Cacoullos | Gauging convergence on the ground: Codeswitching in the community[END_REF]Travis 2015, Adamou 2016). It is of course widely documented for spoken languages that structural congruence can be obtained through calques and indeed calques are encountered in the bimodal data as well. We present in (1) an example from Müller de Quadros, Lillo-Martin and Chen Pichler (this volume) that illustrates, on the one hand, the semantic congruence of the two languages and, on the other hand, a syntactic calque in a bimodal utterance where the spoken component, here English, follows the word order of the signed component, in this case American Sign Language (ASL).

MOTHER WHERE [ASL]

Mommy where [English] 'Where's Mommy?' Müller de Quadros, Lillo-Martin, and Chen Pichler (this volume) suggest that the observed semantic congruence in bimodal bilingual interactions, indicates that bimodal bilinguals form a single proposition (following [START_REF] Emmorey | Bimodal bilingualism[END_REF].

Müller de Quadros, Lillo-Martin, and Chen Pichler (this volume) further argue that bimodal bilinguals use a single derivation, i.e., the mental linguistic computational system incorporates elements from the two languages into a single derivation. The study presented in the paper entitled "A Minimalist Perspective on Code Blending in TİD -Turkish Bimodal Bilingualism" (this volume) supports this approach. The authors show that the elements from the spoken language, Turkish, are not only partly mirrored in the sign language, but that there is a common verb phrase to which the two languages contribute lexically. This can be seen at the level of the verb phrase where 'watch' is expressed in Turkish and 'movie' in the Turkish Sign Language (TID), as illustrated in example (2).

Ben de gid-ip izle-me-di-m [TURKISH] I

too go-CONJ watch-NEG-PAST-1SG I GO MOVIE NOT [TID] 'I didn't go to watch the movie either.' However, [START_REF] Zeshan | Sign-speaking: The structure of simultaneous bimodal utterances[END_REF] provide counter-evidence from Indian Sign Language and Hindi (with minimal English) showing 48% syntactic and/or semantic mismatches. What [START_REF] Zeshan | Sign-speaking: The structure of simultaneous bimodal utterances[END_REF] find instead is that the two propositions share the same communicative intent. To account for the differences in these bimodal bilingual interactions, [START_REF] Zeshan | Sign-speaking: The structure of simultaneous bimodal utterances[END_REF] refer to their data as "sign-speaking". Such differences are reminiscent of the differences between patterns described in "classic codeswitching" (see Myers-Scotton and Jake 2016) and atypical phenomena encountered in mixed languages and in their prior stages of formation [START_REF] Meakins | Mixed languages[END_REF][START_REF] Adamou | Unevenly mixed Romani languages[END_REF][START_REF] Adamou | There are no language switching costs when codeswitching is frequent[END_REF].

Based on the bimodal bilingual data, Müller de Quadros, Lillo-Martin, and Chen Pichler (this volume) elaborate the Language Synthesis model and suggest that the model can account for all bilingual competence, bimodal and unimodal alike. More specifically, the Language Synthesis model is a late lexical insertion model, i.e., abstract roots first enter into the computation of a sentence and Vocabulary Insertion takes place once the Syntactic Derivation is accomplished. In contrast, MacSwan (2014) has elaborated an early lexical insertion model to account for codeswitching, i.e., Select draws the Lexical Items from the two lexicons of the bilingual into the Lexical Array, at which stage, Word Order follows the Lexical Items' properties. Then Merge and other operations lead to the Spell Out in the Phonological Component and the Covert Component. Alternative accounts are based on the psycholinguistic model of speech production in [START_REF] Levelt | Speaking: From intention to articulation[END_REF], namely the Matrix Language Frame model which was elaborated for bilinguals (see for an updated version Myers-Scotton and Jake 2016) and the model elaborated by [START_REF] Emmorey | Bimodal bilingualism[END_REF] for bimodal bilinguals. In future work, the challenge for any model of language production will be to account for both the unimodal bilingual data and the bimodal bilingual data.

A number of interesting findings also come from the studies on sign multilingualism. The paper entitled "Burundi Sign Language-Indian Sign Language bilinguals' community of practice" (this volume) reports on a study that documents the process of constitution of a small bilingual community using two unrelated sign languages, the Burundi Sign Language and the Indian Sign Language. It appears that the bilingual signers develop an unmarked way of communicating which is a mixed way, independent of the duration of stay in India and therefore exposure to the Indian Sign Language. This result brings to mind the data from small bilingual communities which also appear to have patterns of mixing in terms of proportions independent of exposure to the dominant language and dominance [START_REF] Adamou | A Corpus-driven Approach to Language Contact[END_REF]. Similarly, [START_REF] Zeshan | Sign-speaking: The structure of simultaneous bimodal utterances[END_REF] report that, in a trilingual setting, Indian Sign Language and Hindi are frequently used in combination in a typologically rare manner, characterized by frequent syntactic and semantic mismatches, whereas English insertions are more rare and follow the more typical patterns of bimodal bilingual communication, despite dominance of the speakers. This differential treatment in trilingual settings is also found in the interactions of Roma from Greece who exhibit a typologically-rare Romani-Turkish mixing whereas insertions from Greek, the state's official language, follow classic codeswitching patterns [START_REF] Adamou | Unevenly mixed Romani languages[END_REF].

In terms of proportions of signs in the Burundi and Indian community of signers, Zeshan and Panda (2015: 111) have shown that each of the two sign languages contributes 25% to 35% signs that could be clearly identified as being Burundi or Indian. This proportion is more balanced than the proportion found in most bilingual corpora from small communities in which one language is clearly numerically-dominant and the other at best contributes with up to 35% word-tokens [START_REF] Adamou | A Corpus-driven Approach to Language Contact[END_REF]. A possible interpretation of this result could be due to the remaining 40% of similar signs that constitute the majority of the corpus. Indeed, Zeshan and Panda (2015: 111) report that these signers used roughly 40% of signs that the researchers were not able to categorize as belonging to either the Burundi or the Indian sign languages. More generally, unrelated sign languages are known to share a relatively large proportion of signs. This similarity is only partly due to a shared contact language, i.e., American Sign Language, which is the sign language introduced in sign education across the world. The shared vocabulary observed in such cases is mainly due to the iconicity of the manual modality, allowing for signs to be understood without prior knowledge of the language. This feature is of course absent from spoken languages and constitutes a major difference between the languages that rely on the manual modality and those that rely on the spoken modality.

In conclusion, the studies that investigate bilingual communication involving sign languages are of great interest for researchers working on bilingualism and language contact. They allow to shed new light on the theoretical questions that are at the centre of attention in contemporary linguistics and cognitive science. There is no doubt that this is a research field that will continue to grow and contribute to our understanding of the bilingual mind and the use of two or more languages in society. As a linguist working on bilingualism in lesserknown languages, I will definitely continue to follow these developments closely.

Table 1 .

 1 Language contact in sign languages

	sign bilingualism	bimodal bilingualism	sign multilingualism
	sign language A & spoken	sign language A & spoken	sign language A & sign
	language B in writing	language B	language C

The French film La Famille Bélier (2014) by Eric Lartigau nicely illustrates such bimodal interactions.


Nashta grammatical sketch with examples linked to online corpus Evangelia Adamou

CNRS

Background on Nashta

The Nashta variety, literally 'our (language)', is part of the group of South Slavic spoken in the Balkans and represented in the area by two official languages, that is, Literary Bulgarian (ISO 639-3: bul) and Literary Macedonian . Unlike these languages, however, the speakers of the Nashta variety have been in contact with Greek at least for the past century during which the shift to Greek took place. In the scale of endangerment elaborated by Krauss (2006), Nashta can be considered as a critically endangered variety (D).

Recordings and annotation

The texts in Nashta were recorded in the small town of Liti (approx. 2,000 inhabitants), which is located 10 km from the city of Thessaloniki in Greece. The recordings were made in the years 2000 among three fluent speakers, two female and one male, in their 70s at the moment of the recordings, and one younger female semi-speaker. They all use Nashta very rarely, their everyday language being Greek. The recordings took place at home, bringing together acquaintances who were asked to speak Nashta although Greek would have been the language used in these circumstances. Interviews with the researcher completed the corpus.

The texts in this corpus were transcribed in broad phonetics using the International Phonetic Alphabet (IPA). Glosses follow the Leipzig Glossing rules.

Historical background

Liti, where the Balkan Slavic Nashta variety has been recorded, was known as Aivati or Aivatovo during the Ottoman period; see Map in Figure 1. The Tabula Imperii Romani K 3 (1976: 78) attests to the existence of a 'demos of Liti' in 117 BC, whose inhabitants appear to be of Thracian origin. The presence of Slavic agricultural populations in Liti is noted in a seventh-century Byzantine source, entitled The miracles of Saint Demetrius. The relevant excerpt is presented below:

On put alors voir nos concitoyens, [semblables par l'effet de la famine à] des morts et des fugitifs, se rendre avec femmes et enfants aux habitations [sklavènes] des environs de Lite et autres lieux voisins, en ramener du blé et des légumes secs… [We could then see our fellow citizens, [who because of the famine looked] dead and like fugitives, with their women and children, going to the [Slavic] inhabitants around Lite and other neighbouring localities, to get wheat and fruits…] (Lemerle 1979: 207. My translation from French).

It describes the rush of the people of Salonica to the countryside following the end of one of the city's sieges.

Consonants, vowels, and stress

Nashta has voiced and voiceless plosives, voiced and voiceless fricatives, nasals, laterals, a palatal approximant and a short alveolar trill. Voiced plosives and fricatives become devoiced word-finally, e.g., [ˈnoʒ-et] 'knife-ART' but [noʃ] 'knife' in sentence 21, Text https://doi.org/10.24397/pangloss-0000305. See Table 1 andTable 2. Nashta also has affricates, e.g., [tʃ], [dʒ], [ts]. We note that [sʲ] realizations do not only occur in front of back vowels [i, e], as in contact varieties of Northern Greek, but also in front of [a, ae], as in sentence 3, making its phonological status unclear. Indeed, Nashta has two phonemes, /s/ and /ʃ/, while Northern Greek, has one phoneme /s/ realized [s j ] in front of the vowels /i/, /e/, (see https://doi.org/10.24397/pangloss-0000317, sentences 55, 56 aθaˈnasʲios, 69 δimopraˈsʲia) and [s] in front of vowels [a], [o], [u]. In the Nashta corpus we observe the realizations [s], [s j ] and [ʃ] but their distribution is not the direct outcome of the combination of the Nashta and the Northern Greek systems. For example, [s j ] can be realized in front of [a], and can also alter the realization of inherited phonemes as in 'village', realized [ʃelo] Nashta has six vowels, see Table 3.

[ae] appears in the corpus but its status as a phoneme is problematic.

Gender

Nashta has grammatical gender, that is, we find different agreements on the verb, adjective, numeral, and definite article, depending on the gender of the noun (Corbett 2013, WALS 30). Anaphoric pronouns also agree with the gender of their antecedent. Nashta has three grammatical genders: feminine, masculine, and neutral.

Number

Nashta marks plural on the nominals. Interestingly, we note several instances of the old collective -je. See an example in Text https://doi.org/10.24397/pangloss-0000305, sentences 1, 2, 4, ˈʎomperje translated as 'ghosts' by our consultants. However, as collective is no longer in use, we gloss it as a mere plural marker. We note in sentence 32 of the same text the use of the old collective with an article in singular form, ˈʎomperje-to.

Case marking

In Nashta, we can observe the loss of case marking, similar to Bulgarian and Macedonian, but with the exception of several Rhodope and Macedonian varieties that have retained various case markers. In the Nashta corpus we can observe some traces of the vocative; see https://doi.org/10.24397/pangloss-0000341, sentences 24, 26, 27 ˈbabo 'grandmother', but in nominative ˈbaba. We note the use of the same word in Northern Greek dialects, ˈvavo.

Demonstratives

Nashta has a three-way contrast for distance in demonstratives: mid t-, distal -n-, and proximal v-, which is relatively rare in the corpus. Demonstratives in Nashta inflect for gender and number; see 'a couple' in sentence 1, https://doi.org/10.24397/pangloss-0000301, but not with non-referential and generic nouns. We note 2% of bare plural or singular nouns with an indefinite value. However, we do find occurrences of an indefinite article in plural (see https://doi.org/10.24397/pangloss-0000299, sentence 30; iˈdni ˈʒene 'some women'; https://doi.org/10.24397/pangloss-0000313, sentence 13 iˈdni kuˈtie 'some boxes'). The locus of marking in the possessive noun phrases is on the dependent (possessor) and not on the head of the phrase (possessed noun). Possessors in the genitive case agree with the possessed in number and gender.

Adjectives

In Nashta adjectives, expressing a descriptive property such as 'big', 'good', or 'red', precede nouns (AdjN). This order is widespread among the languages of Eurasia, with the exception of Western Europe (Dryer 2013, WALS 87). Adjectives in Nashta inflect for gender and number.

Predicative adjectives

Predicative adjectives in Nashta have nonverbal encoding as typical of languages spoken in the geographical area of Eurasia (Stassen 2013, WALS 118 Predicative adjectives). A verbal copula is typically used although zero copula constructions are allowed (see https://doi.org/10.24397/pangloss-0000303, sentence 4 tajˈfa guˈʎama '(it was a) big family' with inversion of the order of the adjective and the noun from AdjN to NAdj). Nominal and locational predications are encoded through the same devices, as frequently encountered in languages of Eurasia (Stassen 2013, WALS 119 Nominal and locational predications: Identical).

Linear order

Nashta has a dominant verb-object order (VO). The order of the object with respect to the verb can be associated to a number of other typological features. Nashta has prepositions and VO order, two features that correlate in the following way: "if a language is OV then it is usually postpositional and if a language is postpositional then it is usually OV" (Dryer 2011, WALS 95). Nashta has an AdjN order, the adjective preceding the noun. According to Dryer (2013, WALS 97), there is no correlation between the order of object and verb and the order of adjective and noun. In intransitive clauses there is no clear dominant order (Dryer 2013, WALS 82, Order of S and V), but in transitive clauses, the order is generally SVO.

Pronouns Alignment of verbal person marking

Nashta has subject suffixes on the verb (Dryer 2013, WALS 101: Expression of pronominal subjects: Subject affixes on verb). It shows accusative alignment in indexing, where the unique argument of intransitive verbs (S) and the agent-like argument of transitive verbs (A) are indexed on the verb through a single set of suffixes; see Table 10. Notice that third person is zero [START_REF] Siewierska | Alignment of Verbal Person Marking[END_REF], WALS 100: Alignment of verbal person marking). The analysis of the Balkan Slavic data in the light of the differential object marking frame allowed to establish a link between this phenomenon in contemporary varieties and genitive-accusative in Old Church Slavonic [START_REF] Adamou | Le marquage différentiel de l'objet en nashta et en pomaque (Grèce). Retour sur l'hypothèse du contact[END_REF]. This approach also weakened the claim that the Slavic data developed under Romanian and Arumanian or Greek influence [START_REF] Adamou | Le marquage différentiel de l'objet en nashta et en pomaque (Grèce). Retour sur l'hypothèse du contact[END_REF], a hypothesis that is dominant in the literature (Koneski, Vidoeski & Jašar-Nasteva 1968;[START_REF] Cyxun | Tipologičeskie problemy balkanoslavjanskogo jazykovogo areala[END_REF][START_REF] Topolinjska | Makedonskite dijalekti vo Egejska makedonja[END_REF]Markovik 2007;[START_REF] Sobolev | On some Aromanian grammatical patterns in the Balkan Slavonic dialects. In The Romance Balkans[END_REF].

Possessive pronouns

Possession is expressed by a series of free possessive pronouns, that inflect for gender and number, and are generally formed with the definite article, ˈmojet 'my', although indefinite forms are possible, e.g., moj 'my', ˈnegof 'his'. Possessive pronouns precede nouns. See examples in Text https://doi.org/10.24397/pangloss-0000305, sentences 3, 13, 37. The series of indirect object person clitics presented in Table 12, also serves to express possession. In that case the clitics follow the noun; see examples in Text https://doi.org/10.24397/pangloss-0000305, sentences 3 and 23ˈmajka=mu, 14 ˈkəʃce-te=mo, 16 ˈmajciʃi=ne.

Verb

Tense, mood, aspect markers Although the Nashta corpus has few contact words (less than 5%), it shows significant convergence with Greek at the level of the verbal system; see Table 13. This convergence results both from century-long processes within the Balkan Sprachbund and very quick changes within the shifting process to Greek.

Nashta distinguishes between a perfective and an imperfective verbal aspect, the latter being marked through the suffix -uva. We note that some verbs are lexically perfective or imperfective. Preverbs, which are well known for Slavic languages, are not very productive in Nashta. We note the use of preverbs such as na-, iz-.

The past is generally marked through the suffix -x, and in combination with the aspect it is glossed as either "aorist" (AOR) or (IPRF) "imperfect". For example, in https://doi.org/10.24397/pangloss-0000311, sentence 1, the verb 'to watch' is inherently imperfective and thus the -x suffix is glossed as "imperfect", ˈgledaxme. However, in sentence 8 of the same text -x combines with a verb that is lexically perfective 'to see' and thus -x is glossed as an "aorist", viˈdʲaxa. The third person for imperfect has a specific form, -ʃe, as can be seen in sentence 1, ˈbereʃe, and it can combine with the imperfective suffix -uva-, as in sentence 2, sa kaˈtʃuvaʃe.

Nashta has a volitive future formed with the particle ki, an optative with da, and an exhortative with neka, all used with finite verbs. These particles can combine with the perfect and the imperfect forms of the verb, but they are mutually exclusive. The rise of a future based on the volitive 'want' is among the most well-known Balkan features: a 'want'-future is found in Greek, Tosk Albanian, Rumanian, Macedonian, Bulgarian, Serbian and Croatian, and Romani. The use of an optative particle follows the loss of the infinitive which characterizes the languages of the Balkans in general.

Nashta -unlike Bulgarian but like Literary Macedonian -has developed a fully grammaticalized 'have'-perfect [START_REF] Adamou | Le parfait avec 'avoir' dans l'aire balkanique : approche multifactorielle et diversifiée d'un balkanisme[END_REF]. It is characterized by an invariable verbal form based on the neuter past participle and ending in -no/-to. Sentence 14 in https://doi.org/10.24397/pangloss-0000311 illustrates the use of the 'have'-past perfect with a transitive verb, sa ˈimaʃe ˈzeto. Unpublished data also show its use with intransitive verbs such as the verb 'to die', e.g., jima umrjiano ʻhe has died'. Several scholars consider the 'have'-perfect as a Balkan feature, either under Romance influence or under Greek influence, but these analyses remain controversial.

The grammaticalization of a 'have'-perfect with the past passive participle in Nashta probably led to the loss of the former Slavic 'be'-perfect as well as to the even more remarkable loss of all the -l verb forms based on the active participle. Greek was probably a catalyst for the loss of the -l verbal forms; this loss being a unique feature within the Slavic branch. The gradual loss of the -l forms has also been reported for other Balkan Slavic varieties in contact with Greek and is most probably a side-effect of the grammaticalization of the 'have'-perfect. Indeed, in most Macedonian varieties which have no contact with Greek, the rise of the 'have'-perfect led to the use of the -l forms to express evidentiality. The evidential uses of the -l forms are lacking in Nashta, probably because there is no grammaticalized evidential in Greek. Indeed, under Greek influence, Nashta speakers consistently use the aorist or the narrative present for tales as can be observed in this corpus.

Subordinators

Adverbial subordinators, such as 'because', 'when', 'if', are found in the initial position of the subordinating clause.

Borrowings and codeswitching

For the annotation of this corpus, the morphologically and phonologically integrated, single words were considered as borrowings. When borrowings come from the current-contact language they were tagged and appear in italics. When borrowings come from a past-contact language they are followed in parentheses by the code of the language from which they come, e.g., tur for Turkish and rup for Arumanian. Some words can be found in the current contact-language, Greek, and in the past contact-language, Turkish. For example, in https://doi.org/10.24397/pangloss-0000317 in sentences 20, 21, 22, 24, and 26 among others, the word paˈri 'money' comes from Turkish and is most likely a borrowing that took place during the Ottoman era since it can also be found in all the Balkan languages. In Modern Greek, this borrowing from Turkish is integrated with a plural suffix, as paraðes, or in singular as paras, and co-exists with the words lefta and xrimata, 'money'. In this case, borrowings were tagged as 'multiple' (mult) to indicate that although the origin may be a past contactlanguage, the same word is found in the present contact-language in a similar form.

We considered as codeswitching, the phonologically and morphologically non-integrated or multi-word insertions from the current-contact languages. For example, the Greek insertion in https://doi.org/10.24397/pangloss-0000317, sentence 55, ˈaɟos aθaˈnasʲios, is followed in sentence 58 by its equivalent with native material, sfiˈti ataˈnas. In sentence 55, the first occurrence of the cluster 'Saint-Athanasius', ˈaɟos aθaˈnasʲios, shows partly phonological adaptation with [ɟ], immediately followed in the repetition by the Greek [j] in sentence 56 ˈajos aθaˈnasʲios. The Greek [θ] is kept in both cases as opposed to the integrated form seen in sentences 58 and 64 as sfiˈti ataˈnas, with [t]. In sentence 55, the Greek insertion of the cluster 'Saint-Athanasius' is not integrated into Slavic as it keeps the Greek nominative case. Also see sentence 2, https://doi.org/10.24397/pangloss-0000315 for similar variation between the Greek form, with the genitive case, and the Slavic equivalent, aˈʝiu aθanaˈsiu sfiˈtij taˈnas. We note that word order is identical in the two languages, i.e., adjective-noun.

The Balkan Slavic Nashta corpus, shows less than 5% Greek words from all word classes. Very few word classes from Greek are concerned, namely nouns (33% of all nouns) and a small number of verbs. Tokens from other word classes may occur but in a peripheral way [START_REF] Adamou | Borrowing and contact intensity: A corpus-driven approach from four Slavic minority languages[END_REF].

Noun borrowings from Greek

The Nashta corpus shows a variety of nouns in lexical domains which are generally known to be affected by contact. Table 14 illustrates the Greek nouns found in this corpus following an organization by lexical semantic fields. Story, clearly reveals the mistake of the Bulgarian scholars, as it would be rather amusing that the speaker refers to the 'pears' in the video as being collected from an 'oak tree'; ɟi ˈbere ˈprisʲiŋɟi-te ɟi ˈklava ut ˈfut-ta ɟi ˈklava u ˈkoʃnətsə-ta. ˈskal-ta tam ˈstoi u ˈdəb-at udˈgore. Indeed, it is common in several Balkan Slavic dialects that the specialized meaning for 'oak' has been extended to the more generic meaning 'tree'.

Figure 1 .

 1 Figure 1. Map from 1903 1 indicating the village of Ajvati (nowadays Liti) nearby the city of Saloniki (nowadays Thessaloniki)

Figure 3 .Figure 4 .

 34 Figure3. Variability of F1 and F2 values of stressed vowels in Nashta produced in the spontaneous speech of a female speaker[START_REF] Adamou | A corpus-driven approach to language contact: Endangered languages in a comparative perspective[END_REF]

Table 3

 3

	. Vowels
		front central back
	close	i	u
	close-mid		ә
	mid	e	o
	open-mid	ae
	open		a
	Table 4. Vowels, stressed and unstressed
		STRESSED		UNSTRESSED
	i	ˈlisto	'leaf'	iˈdno	'one.SG.N'
	e	ˈmeso	'meat'	ˈsirne	'cheese'
	ә	ˈvəlna	'wool'	məˈrafka	'ant'
	ae	ˈdaetsa	'children'
	a	ˈxabalka 'apple'	ˈʒena	'woman'
	o	ˈkotka	'cat'	ˈmeso	'meat'
	u	ˈfurna	'oven'	ʃuˈkaj	'scarf'
	Nashta has stress, that is, stressed syllables are longer than unstressed syllables
	and have differences in vowel quality. Stress falls mainly, although not
	exclusively, on the penultimate in the native parts of its vocabulary.
	Most vowels present substantial variation in pronunciation, within individual
	speakers and between speakers. The phonetic variation in the realization of the
	vowels is captured by a pilot phonetic study of this text based on a digital speech
	analysis software. Semi-automatic alignment was run with EasyAlign by
	phonetician Martine Toda. 2 It was then possible to run a semi-automatic script in
	Praat with the "log file 4" and "triangle vocalique" scripts. 3 Figure 2 illustrates
	the mean F1 and F2 for the stressed (in grey) and unstressed (in black) vowels
	based on 455 tokens produced by a female speaker in Text
	https://doi.org/10.24397/pangloss-0000305. It can be seen that the mid vowels /e/
	and /o/ are not raised to [i] and [u] as is the case in the contact-varieties of
	Northern Greek. Figure 3 shows the variability of F1 and F2 values of stressed
	vowels and Figure 4 of unstressed vowels. It can be seen that unstressed /a/ and
	/e/ are realized in a very similar area. We also note a significant overlap for /a/
	and the non-

phonological [ae], (see Text https://doi.org/10.24397/pangloss-0000305, sentences 1 ˈvraeme, 3 ˈtaejko, 12 ˈsfaetixa, 14 ˈbaeʃe, 16 tsae, among many others), as well as for /e/ and /ə/. In contrast, there is no overlap between /o/ and /u/ as well as between /i/ and /e/.

Figure

2

. Mean F1 and F2 for the Balkan Slavic Nashta stressed (in grey) and unstressed (in black) vowels based on 455 tokens produced in the spontaneous speech of a female speaker

[START_REF] Adamou | A corpus-driven approach to language contact: Endangered languages in a comparative perspective[END_REF]

Table 5

 5 The tforms in sentences 30, 38, 40, the nforms in sentences 1, 17, 25, 28, and the vforms in sentences 7, 15, 45. However, only a few Slavic languages have grammaticalized definite articles: this is the case for South Slavic. The grammaticalization of postposed articles in South Slavic results from both internal and contact-induced factors, as it coincides with a similar development in the Romance languages of the area (Romanian, Aromanian, and Meglenoromanian) and Albanian. Definite articles in South Slavic were grammaticalized from demonstratives, a cross-linguistically common development. Written sources show that the postposed demonstratives attested in Old Church Slavonic documents (between the ninth and eleventh centuries) were grammaticalized into clitic demonstratives and then into clitic articles. Literary Bulgarian has a single definite article but Literary Macedonian and the Rhodope varieties have three definite articles.

	3000	2800	2600	2400	2200	2000	1800	1600	1400	1200	1000	800
													200
													400
						i					u
	(Hz)							e	a		o		600
	F 1												800
													1000
													1200
						F 2 (Hz)

. In Nashta, the demonstrative precedes the noun as commonly found in most languages of Eurasia

(Dryer 2013, WALS 88)

. For examples see Text https://doi.org/10.24397/pangloss-0000305 Nashta has a single definite article, based on the -t form, inflecting for gender and number; see Table

6

. The analysis of the corpus shows that 83% of all the nouns in the corpus are determined by a definite article, a high percentage indicating that definite articles are probably fully grammaticalized in Nashta. Greek influence can be seen in the use of the Nashta definite articles with proper nouns, impossible in most Slavic languages of the area; e.g., Text https://doi.org/10.24397/pangloss-0000321, sentences 4, 5, 6. https://doi.org/10.24397/pangloss-0000301, or with referential nouns, e.g., iˈdin aˈndroʝino

Table 7 .

 7 Indefinite article in NashtaDegree words In Nashta, the order of a degree word, e.g., ˈmnogo 'very', po 'more' (see sentences 28, 29 for 'very' and 4, 9, 16 for 'more', https://doi.org/10.24397/pangloss-0000317), and the adjective it modifies is DEG-ADJ, where the degree word precedes the adjective. This is another common feature among the languages of Eurasia (Dryer 2013, WALS 91). /doi.org/10.24397/pangloss-0000305 for examples for kinship, sentence 37 kateˈrin-ta ˈnejn-ət peθeˈros, and ownership, sentence 11 xadʒiˈɟorɟeve-te ˈkəʃce).

	Singular Masculine iˈdin
	Feminine iˈdna
	Neutral	iˈdno
	Plural	iˈdni
	Numerals
	Numerals in Nashta precede nouns (NUM-N). We note that distributive
	numerals are marked by a preceding word, po/pu, see sentence 31,
	https://doi.org/10.24397/pangloss-0000317 po sto ˈfraŋga; sentence 15, Text
	https://doi.org/10.24397/pangloss-0000305 ˈʝimaʃe pu iˈdin ˈkamen.

Prepositions

Nashta has prepositions, similar to most languages in Europe (Dryer 2013, WALS 85). See Tables

8 and 9

for the temporal-spatial prepositions. See examples in Text https://doi.org/10.24397/pangloss-0000321: u 'locative, punctual

', sentences 2, 18, 27, 33, na 'allative, durative', ut 'ablative', sentences 25, 27, 32, 38, dur 'limitative', sentence 17.

Table 10

 10 ˈʎomperje ʝa na ˈʎomper ʝa ci gu uˈbija, 7 ʝa vo ˈvetʃer ci ˈpoʝa ˈvoŋka, 45 arˈtlik ˈela da ti ˈkaʒe ʃo tʃiˈnix ʝa vo ˈvetʃer, 50 ʝa ˈveʎe pak za ˈʎomper ˈveʎe gu (ud)vəˈrvjax. Table11shows the forms of the free person pronouns.Nashta has two series of person clitics, one for direct objects (glossed ACC) and one for indirect objects (glossed DAT); see Table12. Both series precede the verb, including clause initially. When the two clitics co-occur, the indirect object clitic always precedes the direct object clitic. We note some variation in the forms of the clitics for first and second person. The person clitics can cross-reference a noun when the noun is determined by a definite article or a possessive pronoun; this is the so-called "clitic doubling".

	. Person suffixes
	Person	Subject/Agen
		t
	1SG	-m
	2SG	-ʃ
	3SG.M/F/	Ø
	N
	1PL	-me
	2PL	-te
	3PL	-t
	Free person pronouns
	Nashta is a pro-drop language, i.e., the free pronouns are not obligatory but
	appear in marked contexts; see Text https://doi.org/10.24397/pangloss-0000305
	sentences 5 Table 11. Free person pronouns
	Person	Subject/Agent	Indirect object following
		(NOM)	a preposition
			(DAT)
	1SG	ja	ˈmene
	2SG	ti	ˈtebe
	3SG.M/	to	ˈnego
	N	ta	ˈneja
	3SG.F
	1PL	ni	nas
	2PL	vi	vas
	3PL	ˈtie	nix
	Person clitics and clitic doubling
			See examples in Text
	https://doi.org/10.24397/pangloss-0000305, sentences 5, 10, 30, 43, 46, 47. See
	https://doi.org/10.24397/pangloss-0000319, sentence 78 for a case of co-occurrence
	of the free person pronoun and the clitics; na nix mu=ˈdavaxa 'they gave to them'.

https://doi.org/10.24397/pangloss-0000309, sentence 1 e u ˈgledam tsae na to sə ˈbere ˈprisʲiŋɟe), or in Text https://doi.org/10.24397/pangloss-0000305 for humanlike objects, as in sentence 46 for the 'ghost' ʃo tʃiˈni gu provaˈʎix na ˈʎomper-ət.

Table 13 .

 13 Verb morphology in Balkan Slavic Nashta and Greek (Adamou 2016) /doi.org/10.24397/pangloss-0000307 sentences 4 sa ˈklavaxme, 18 sa ˈimaʃe for more examples. The reflexive, reciprocal, and middle always precedes the verb, including clause initially. Table 14 summarizes all the possible uses.

			Nashta		Greek
	volitive		ki			θa
	optative		da			na
	exhortative	neka			as
	imperfective	-uva-			stem morphology
			or stress
	'have' perfect	imam Vinv(-no)	exo Vinv.
	Reflexive, reciprocal, middle
	Nashta has an uninflected reflexive, sa, which is also used as a reciprocal, e.g.,
	https://doi.org/10.24397/pangloss-0000301, in sentences 1 sa ˈkaraxa, 3, 4, and as a
	middle, e.g., in sentences 15 sa stənaxoˈresa, 16 ci sa iˈstemne, 19 sa varˈna. It
	always	precedes	the	verb,	including	clause	initially.	Also	see
	https:/Table 14. Reflexive, reciprocal, and middle
	Form	Construction		Use
		intransitive		Middle
	sa	intransitive		Naturally reciprocal
		transitive,		Reflexive
		attributive
	Syntax
	Relative clauses
	Nashta has externally-headed relative clauses where the relative clauses follow
	the head nouns (NRel).

Table 14 .

 14 Lexical semantic fields of Greek nouns in the Nashta corpus Greek verbs are integrated in Nashta with the Greek aorist marker -s-. In Nashta, however, the -s-aorist marker does not keep the initial aoristic value as Text https://doi.org/10.24397/pangloss-0000309, based on the video stimuli Pear

	Semantic fields	Word
	Food and drink	pçato 'plate'
		tindʒir 'pot'
		skurdar 'garlic mixture'
		liparide 'kind of fish'
		kulur 'round loaf'
		laŋɟide 'fritters'
	Animals	kotopulo 'chicken'
		kukuʎ 'cocoon'
	Physical world	mura 'mulberry tree'
		kalamɲe 'rose branches'
	Basic actions and technology putir 'glass'
		paner 'basket'
	House	lamba 'lamp'
		kandil 'candle'

EasyAlign is developed by Jean-Philippe Goldman, University of Geneva.

Developed by Cédric Gendrot, see http://gendrot.ilpga.fr/scripts.htm

We also note the change of the original transcription into Bulgarian script, the absence of the original glosses as well as the absence of the citation of the author and change of the village's name according to the Bulgarian dialectological tradition from Liti to Aivatovo.

Corbett, G. G. (2013). Number of Genders. In: Dryer, M. S. & Haspelmath, M. (eds.) The World Atlas of Language Structures Online. Leipzig: Max Planck Institute for Evolutionary Anthropology. (Available online at http://wals.info/chapter/30, Accessed on 2017-07-25.) Dryer, M. S. (2013). Definite Articles. In: Dryer, M. S. & Haspelmath, M. (eds.) The World Atlas of Language Structures Online. Leipzig: Max Planck Institute for Evolutionary Anthropology. (Available online at http://wals.info/chapter/37, Accessed on 2017-07-25.) Dryer, M. S. (2013). Indefinite Articles. In: Dryer, M. S. & Haspelmath, M. (eds.) The World Atlas of Language Structures Online. Leipzig: Max Planck Institute for Evolutionary Anthropology. (Available online at http://wals.info/chapter/38, Accessed on 2017-07-25.) Dryer, M. S. (2013). Order of Subject and Verb. In: Dryer, M. S. & Haspelmath, M. (eds.) The World Atlas of Language Structures Online. Leipzig: Max

Planck

Institute for Evolutionary Anthropology. (Available online at http://wals.info/chapter/82, Accessed on 2017-07-25.) Dryer, M. S. (2013)