E-learning as a touchstone for didactic theory, and conversely

Yves Chevallard and Caroline Ladage UMR ADEF Aix-Marseille Université, INRP

Didactics and ATD

E-learning is a somewhat ill-defined concept, but it is a fruitful one, insofar as it allows or even compels one to reconsider one's own views about more traditional ways of teaching and learning. Despite the title of this paper, let's make it clear from the start that we shall not indulge in comparing meticulously two hypostatized entities, "traditional" versus, say, "electronic" teaching and learning. In what ways can e-learning be regarded as a touchstone will become evident in what follows. On the other hand, we shall stick to what has come to be known, in many countries, as the anthropological theory of the didactic (ATD), a theory upon which we shall draw heavily in the sequel. (To go beyond what we shall make explicit hereunder on ATD, we refer the interested reader to, for example, [START_REF] Chevallard | Readjusting Didactics to a Changing Epistemology[END_REF]) ATD defines didactics as the (incipient) science whose object is the structure and dynamics of the more or less fuzzy set of conditions and constraints that determine the controlled diffusion of knowledge and skills in society. (In this respect, ATD appears as a development program for didactics: although there can be different routes to the same state, it proposes itself as a freeway to a full-fledged scientific field in education.) A word of comment is in order here on the concurrent use of the closely related notions of "condition" and "constraint": both are to be construed as determining factors of diffusion (and of retention, seen as a limiting case of diffusion) of knowledge; but while conditions are supposed to be adjustable (they lay within the reach of the development team, a notion to which we shall return), constraints are limiting factors presumed to remain unchanged (and out of reach) under present circumstances, even though circumstances may vary in a distant future.

Didactic Organizations and Didactic Systems

The notion on which this presentation really centers is that of a didactic organization (DO), a notion that subsumes all the features of whatever learning or teaching scheme one might think of, be it fashionable or obsolete. A didactic organization cannot exist unless some set of learning objectives has been determined; in ATD's parlance, these objectives constitute the didactic stakes on which the whole DO hinges. To make a long story short, we shall accept here the view that any didactic stake can be translated into some question Q to which an answer A has to be brought, a pursuit that the didactic organization is supposed to ensure.

Although a DO has indeed a multilayered structure -essentially, it is made up of a "school" layer, a pedagogical layer, and a (purely) didactic layer -, we shall not distinguish them here, applying indifferently the adjective "didactic" to any of these layers. With this in mind, one can say that a DO should guide the makeup and functioning of a didactic system (DS)another keyword of didactics. A DS is made up of three main entities. The first one will be denoted by X and called the community of study, or community of students, that is the "learning community", which, for that matter, is seen as a community of "peers". The second one is denoted by Y: it is the set of "study aides" -including the "teacher", or "instructor", or "trainer", or "tutor", or what have it-who officially engage in helping X to study question Q in order for X to build up some (valid) answer A to question Q. In some DOs, members of Y may direct the study process, as any teacher is used to do, which is a most traditional way of "helping" students. The corresponding DS can be denoted by S(X;Y;Q), while the outcome of the whole study process is summed up by the "formula" S(X;Y;Q) → A. Now, any DO must attend to a number of crucial issues, as for example turning a set of individuals, be they would-be "students" or potential "study aides", into a community X and a teaching team Y, two challenges in their own right. How can a DO, one must ask then, solve this problem? As concerns X, for instance, there exist traditional classroom solutions which consist essentially in having people gather in a "classroom" under the lead of a teacher or instructor and be made into a group through continuing, daily classwork. About the same trick can be applied to the building-up of Y, although traditional usage is simply to let Y be a singleton-"the" teacher-, a manoeuver which reduces the problem to nought. Such "solutions" have come to look natural to most of us, unless face-to-face teaching-sometimes called "presential teaching" in the international literature on the subject-was ruled out by some peculiar, compelling situation, thereby giving rise, in a case of force majeure, to "distance teaching" seen then as a makeshift.

From distance education to e-education to "new" education

At this point, it is necessary to clarify one important point of terminology. As anyone knows, distance teaching (or education) existed well before the Internet was born-it should be enough, in this respect, to mention Descartes' "snail mail" correspondence with Princess Elizabeth of Bohemia. But e-learning has rejuvenated distance education by providing scores of fresh tools to a job that, until not long ago, looked didactically depressed. Distance education has thus entered a second life, in which snail mail education gives way to eeducation. Now it will be our main contention that the many solutions recently brought to oldfashioned distance learning by e-technology give rise to a tremendous opportunity for unprecedented development-through the definition and diffusion of "hybrid" or "blended" DOs-, not only of distance learning, but also of the existing face-to-face, traditional ways of studying. Provisionally, in this paper, we dub "new didactics" the field of study devotedwithin the framework of ATD-to "new education", that is to the panoply of actual or as yet potential "hybrid" DOs thus marked off. New didactics thus essentially boils down to exploring-both theoretically and empirically-new didactic organizations resulting from the changes e-technology enables us to bring to plain, unadorned didactic organizations.

The didactic hyperspace: its multifarious resources and unexpected pitfalls

Probably the main new concept of "new didactics" is the notion of didactic hyperspace. In traditional teaching organizations, one can distinguish the principal didactic system (PDS), in which the whole community X meets at regular intervals in order for everyone to find one's bearings, from auxiliary didactic systems (ADS), in which the class is usually divided into smaller groups, as happens in homework, tutored group work, lab sessions, etc. By contrast, in new education, for any given didactic system, one can think of a multitude of types of sessions, made possible by the embedding of traditional didactic space in what will be aptly called a didactic hyperspace, that is, a space having more "dimensions" than the traditional didactic space. (The name "hyperspace" draws on a mathematical metaphor, exactly as Ted Nelson did when, back in the 1960's, he coined the word "hypertext" to label a "higherdimensional" text.) Considered in the vaster hyperspace brought about by e-devices, any didactic organization, supposed (often implicitly) to be optimal (or close to an optimum) with respect to traditional didactic space, will no longer be so-it becomes suddently sub-optimal.

Ways to upgrade it, at least slightly, never fail to come to mind readily, like having students email their homework assignments to the teacher before some prescribed deadline, to quote just a minor example. In keeping with the standards of didactic engineering, the design of "new", that is "mixed", DOs is here supposed to rest on a development team T which should at least include a specialist in didactic engineering and a technology expert, and whose intersection with Y is usually non-empty (the teacher or instructor generally belongs to T). Now, although the aim of T is to create more optimal DOs, it does happen that changing a timeworn DO into a brand-new one sometimes moves it farther away from the optimum. It may be, for instance, that the teachers' commitment to their role declines, because they have interiorized the belief in the erroneously supposed quasi-autonomous functioning of digital technology in education. The didactic hyperspace abounds in potential "new" solutions to the fundamental issues of education that remain to be ascertained. In this respect, "new" education (as we term it here) is the new frontier of education; and "new" didactics is a field of endeavor open to new scientific and engineering energies. But care should be taken not to fall into the next trap.

The problem with e-tools

It is sound to remember that "new" education is in beta-testing-or maybe alpha? One of the main problems teaching institutions meet in this respect relates to the gamut of available etools and their broad range of complexity of use. To take just one example, in its "25 Tools A small number of remarks are in order here. Firstly, it is striking that most if not all of these tools are not specific to education, and that their relevant didactic uses remain to be conquered. Secondly, it is very likely that many people in the field of education will not make sense of each and every item on the list: "new" education is really new (see also Neidorf, 2006, chap. 1). Thirdly, as concerns functionalities, there is some overlapping between all these tools: for example, forum discussion tools, which often showed up in the literature on e-learning at the turn of the twenty-first century, have been since then subsumed within tools like course management systems (CMS) or learning platforms.

Fourthly, if all members of T, Y, and X must have some working mastery of these and other tools, the right knowledge of them will depend on whether they act as developpers (T), "study aides" (Y) or students (X). This indeed is a crucial point. Beyond the "material" organization, which is first and foremost the development team's responsability, the proper functioning of any didactic organization requires the "enactment" of some sort of contract, that will make clear what the distinct roles connected to the DO are, and that regulates the doings of every kind of "participants" to it. Now, observance of this contract entails a shared world of meanings and a collective (though differentiated) mastery of the devices on which the DO draws. In too many cases, it seems, insufficient care is given to this problem, which can be conducive, to say the least, to confusion on the part of the students, for instance. One formerly "traditional" instructor, so the story goes (Ko & Rossen, 2000), had simply added in his course syllabus for some academic year the words "This course is delivered completely online." But the syllabus still referred to "class sessions", to take place once a week. While some students conjectured this alluded to real-time chat, others made sense of it by believing that "their asynchronous communications should be posted only once a week, on the particular day named in the schedule." But the real problem, from a didactic point of view, is all the other way round [START_REF] Nichols | A Theory for eLearning[END_REF].

Didactic (hyper)time

It is a common problem of education (and maybe of human activity in general) that structure is often given precedence over functions: e-tools come first, while the consideration of didactic (functional) needs lag behind and often comes too late. Much to the contrary, a sound view of didactic engineering calls for the reverse: didactic functions, not structures, must be considered first. Indeed, this always happens in some measure, but implicitly-and not always for the better. In fact, most designers of e-tools, who are high-tech people, usually are (unconsciously) stark traditionalists when it comes to the didactic world, so that many available products covertly and naively lend support to antiquated views about course-based learning. The main problem then is no longer to list the possible uses of a given e-tool, but to determine how a given didactic function can be ensured by resorting to a given (although extensible) panoply of tools. In passing from the "traditional" toolset to e-tools, some didactic features may be blurred, or even more deeply altered; but there are didactic invariants, and these should be prioritized. The first main didactic function that we tackle here is that of didactic time. Any DO, as designed by T, must allow Y and X jointly to generate didactic time.

Didactic time is a segmentary-not continuous-time, made up of (oriented) "segments" or pieces of knowledge that are usually marked out by Y-the teacher, in classical DOs-for study by X. Depending on the concrete study process that will take place, a didactic segment can be divided into many "subsegments". But a standard segment of didactic time begins-in the didactic paradigm we adopt here-with a question Q, or more precisely with that didactic moment in which X encounters some new question Q, then recognized by Y as a question whose study will be devolved on X. Such a symbolic and substantial enactment originates new progress in didactic time. While the initial endpoint of a didactic segment consists in a question Q (or rather its devolution on X), its terminal endpoint coincides with an answer A, or more precisely with that didactic moment in which the answer worked out by X under the supervision of Y is duly institutionalized, i.e. made officially into a part of X's knowledge.

The march of didactic time thus provides the study process with its essential framework: didactic time is didactic history reduced to its basic constituents. Now the big problem that arises is this: in traditional teaching, both the devolution of Q and the recognition and institutionalization of A are face-to-face events; how can that be achieved differently, taking advantage of the potential of didactic hyperspace? Many answers may come to mind, for example answers that do not yield to the tyranny of being there physically: one can think of a (synchronous) half-hour Web conference to assign X work that will lead them to encounter question Q, followed some time later by an online (asynchronous) synthesis "session", using a Web forum on which contributions from students (or teams of students) will be posted, in order that a synthesis circumscribing question Q might soon be established. For lack of space, we shall not delve any longer into the detail of this process. However, it is of utmost importance to emphasize that didactic time is thus reduced to a small number of (synchronous or asynchronous) "gatherings", which fix the collective pace of study, while all the clock's time left (in the preceding example, the time elapsed between the Web conference and the Web forum deadline) can be freely allotted to self-paced study (which, in this particular case, has to open the way to the collective formulation of question Q). The structure of didactic hyperspace transmutes didactic time into a somewhat more complex notion, which can be termed didactic hypertime. Mastery of didactic hypertime is one fundamental aspect of mastery over didactic hyperspace.

Didactic ambiguities in e-learning

Much more remains to say about the didactic process and how it can draw on the resources of didactic hyperspace. Beyond the so-called chronogenesis of X's newly shared knowledge (which correlates with the flow of didactic time), two major features organize study. The first one, the so-called topogenesis, has already been touched upon implicitly: at any point in time, The answer given to this issue will draw a sharp dividing line between competing didactic paradigms. Some course management systems seem to be-at least unintentionally-conservative and to suit surreptitiously old-fashioned teaching and learning styles. This shift toward the past can be described in terms of topogenesis, using the "variables" T, Y, and X. In most course packages, every detail seems to have been decided upon by T-by the "instructional designer", or the "topic expert", or even the software developer, notably-with almost nothing left to Y to determine. Such a "teacher-proof" course would make Y into a (collective) underling. But one must go further in this respect: in classical teaching, it is even more usually the case that every detail of a learning "program" is fixed by Y, with little or no place left to X's initiative. In the following, we adopt a quite different view, for which we need to supplement the formula S(X;Y;Q) → A to arrive at this:

[S(X;Y;Q) → M] → A.
Here, M denotes the didactic "milieu", i.e. the set of resources to be used to "develop" answer A. In the most traditional teaching styles, A is brought ready-made before X by the teacher, so that the problem of M can be altogether ignored. By contrast, in the didactic problematic we refer to here, the elements in the milieu M have to be selected and arranged to serve as the tools and materials needed to "erect" A. In classical teaching, mesogenesis-Greek mesos meant "middle"-could rest on Y entirely, so that Y used to provide M ready-made to X. In contradistinction, we shall advocate yet another step forward to give X a larger topos, according to which students will play a central role in the construction of both M and A. The DO set up to get S(X;Y;Q) working must therefore allow X to carry out, under Y's supervision, this crucial didactic function. In this perspective, it now transpires that the list of e-tools given above, which is typical of current literature on eelearning, fails to include one major category of learning tools-Web search tools, and notably search engines, which in our view should be part and parcel of a reasonable eequipment. Let us conclude by asserting unequivocally that one cannot earnestly assess any etool without referring explicitly to some definite didactic model, in order to raise didactically relevant questions about its potential functionality and usefulness as an organizational ingredient.

The world around e-learning

Many more aspects would be worthy of careful consideration. Stress has thus been put on the role played by apparent trifles in the success or failure of a determined e-DO. For instance, one author [START_REF] Wymer | The Professor as Instant Messenger[END_REF] narrates how her efforts to use instant messaging (IM) to better comunicate with her students-who found e-mail "dinosaur-ish"-rapidly proved unfruitful, because these students still regarded IM as pertaining to youth culture and therefore as inappropriate for academic communication. In the opposite direction, another author [START_REF] Young | Forget E-Mail: New Messaging Service Has Students and Professors Atwitter[END_REF] emphasizes the relevancy of microblogging, that is sending very short notes (up to 140 characters) to a whole class of students. Referring to an assistant professor of emerging media and communication's experience, Young states that, in this case, "the immediacy of the messages helped the students feel more like a community." Although these facts cannot be ignored, they are but circumstantial expressions of otherwise permanent cultural traitsyouth's defensive attitude towards the world of adults, on the one hand, and taste for novelty, on the other. Some other facts, which are less conspicuous, have more far-reaching consequences. School is still predominantly a world of orality, i.e. a world in which writing only complements speech, by providing aide-mémoires-"memory aids"-, memorandums, reminders, and records of live utterances (Ong, 1982, p. 84). The written word is thus a secondary character lending support to the real protagonist of the play, the sounded word. Now, notwithstanding the indisputable remark that "the electronic medium is neither exactly like speech nor exactly like writing" (Crystal, 2006, chap. 24), the e-world has inevitably shifted the ordinary oral culture towards some form of written communication-even if Carl Carlson, the fictional character in the animated television series The Simpsons, could still define an e-mail as "a quiet phone call". The point is that, save for a minority, teachers were never fully "men of letters"-they are lectores, not auctores, "lecturers", not "authors". But personal writing is a necessity of sound e-teaching; and this may repel many a traditional teacher or instructor from coming to grips with e-tools. On this point, some form of silent, cultural revolution is still pending.

  Programme", The Centre for Learning & Performance Technologies Web site puts forward the following list of 25 e-tools: 1) Web browser; 2) Email tool; 3) Instant messenger; 4) Social bookmarking tool; 5) RSS reader; 6) Real-time messaging tool; 7) Online Calendar; 8) Office suite; 9) Mind mapping tool; 10) Start page tool; 11) Blogging tool; 12) Web authoring tool; 13) Wiki tool; 14) Photo hosting and sharing tool; 15) Presentation hosting and sharing tool; 16) Video hosting and sharing tool; 17) Collaborative presentation tool; 18) Podcasting tool; 19) Screen capture/casting tool; 20) Polling and survey tool; 21) Web meeting tool; 22) Live broadcasting tool; 23) Social networking tool; 24) Course authoring tool; 25) Course management tool.

  both Y and X must know what they have to do next. They must understand what their part is, what their role is made of; in other words, they must know what their "place" is-Greek tópos meant "place."


Alexis Michaud
email: alexis.michaud@vjf.cnrs.fr

He Xueguang

Reassociated tones and coalescent syllables in Naxi (Tibeto-Burman)

The Western dialect of Naxi has four lexical tones: High, Mid, Low and Rising; the latter is rare in the lexicon. Rising contours on monosyllables are frequent in connected speech, however, as a result of a process of syllable reduction: reduction of a morpheme carrying the High tone results in re-association of its tone to the syllable that precedes it in the sentence, creating a rising contour. An experiment (with one speaker and five listeners) establishes that there is not only one rising contour that originates in tonal reassociation, as reported in earlier descriptions, but two: Low-to-High and Mid-to-High-as could be expected by analogy with phenomena observed in Niger-Congo languages and elsewhere. A second set of experiments (same speaker; six listeners) investigates the reduction of Mid-and Low-tone syllables: they reduce to [ə] and [ə], respectively, and coalesce with the preceding syllable (in Naxi, syllabic structure is simply consonant+glide+vow l).

Unlike High-tone syllable reduction, this process stops short of complete tonal de-linking. These experiments aim to provide a complete picture of syllable reduction patterns in Naxi. It is argued that the notions of floating tones and tonal reassociation can be usefully applied to the Naxi data.

Introduction

The Western dialect of Naxi (纳西, a.k.a. Na 纳, Moxie 麽些, Moso 摩梭), a Tibeto-Burman language spoken in China, could appear as a textbook example of a level-tone language: each syllable carries a High ( ), Mid ( ), or Low ( ) lexical tone (He & Jiang 1985: 10). A rising lexical tone is also reported on a small set of native monosyllables as well as on numerous (monosyllabic) loanwords, resulting in minimal quadruplets such as the following: /lɑ/ 'to strike', /lɑ/ 'tiger', /lɑ/ 'hand', /lɑ̀ / 'candle'. Rising contours are also created in connected speech by a process of syllable reduction: some monosyllabic morphemes carrying High tone can undergo a form of reduction whereby their segments are deleted and their High tone associates to the preceding syllable. If the latter has a lexical Low or Mid tone, it acquires a rising contour; if it has a High lexical tone, this tone remains unchanged. This is reminiscent of phenomena found in other languages-typically in languages of the Niger-Congo family, as described by Goldsmith (1976), but also in other families, e.g., among creole languages, in the variety of Saramaccan studied by [START_REF] Good | Tonal morphology in a creole: High-tone raising in Saramaccan serial verb constructions[END_REF]-which are now commonly modelled in terms of association lines between a tonal tier and a syllabic tier, as in (1a-b) below: when syllable σ 2 undergoes reduction (full deletion of its segmental contents, i.e. disappearance of σ 2 from the syllabic tier), its tone, T 2 , reassociates to syllable

σ 1 . (1a) σ 1 σ 2 (1b) σ 1 T 1 T 2 T 1 T 2 page 3 ________________________________________________________________________________________________________________________________________ e c ex c
Earlier accounts of Naxi [START_REF] He | 纳西语简志 N xiyu Jia hi (A Brief Monography on the Naxi Language)[END_REF]: 15, 54, He Zhiwu 1987: 61) only acknowledge one rising contour. For instance, He Jiren and Jiang Zhuyi (1985: 15) This notation reflects the belief that the four lexical tones of Naxi are High â, Mid î, Low-falling ö and Low-rising ï, and that the elliptical construction (2b) results in the creation of a Low-rising contour identical to the lexical Low-rising tone. By analogy with phenomena observed in Niger-Congo languages and elsewhere, the first author of the present article hypothesised (i) that the 'Low-falling' tone of Naxi was simply a Low tone, and (ii) that two contours resulting from syllable reduction were to be distinguished, the rising contours observed in continuous speech corresponding either to Low plus High ( ̀́),

or to Mid plus High ( ̄́). Thus, (2b) would be transcribed as: /dɯ̄. The explicit phrasing is the following:

(3b) ŋɤ̀ ʈʂʰɯ̄ kʰɑ̀ tɑ́ ʈʂʰū lù tʰv̩ ̄ mɤ.

'I've only just arrived here. (= I'm a newcomer here.)' (Same glosses as (3a); /tɑ/, 'only', is not reduced.)

The syllables involved in this process are typographically emphasised for the sake of clarity.

In (3a) the segments of adverb /tɑ/ are deleted, and its tone is reassociated to the preceding syllable, /kʰɑ/ 'moment'; the stylistic nuance is, predictably, that (3b) is more colloquial than (3a). This is frequent in connected speech, as illustrated in figure 1, which shows a spectrogram and fundamental frequency (hereafter F 0 ) tracing of an excerpt from a narrative, (4):

[INSERT FIGURE 1 HERE]

In (4), the rising contour on the verb 'to fetch' points to an added High tone; this High tone is due to the reduction of the grammatical word /pú/. As a verb, /pú/ means 'to bring, to offer'; in its grammaticalised uses, it has been described as a 'gerundiser' by Pinson (1998: 11). A synchronic overview of High-tone syllables that can undergo reduction to a High tone, which reattaches to the preceding syllable, is provided in Michaud (2006a).

Section 1 describes experiments on High-tone syllable reduction. It is argued that the notions of floating tones and tonal reassociation can be usefully applied to the Naxi data.

Section 2 aims at presenting the broader picture of syllable reduction in Naxi by investigating the reduction of Mid-and Low-tone syllables to a coalescent [ə] and [ə],

respectively. This process stops short of complete segmental deletion and 'tonal de-linking'.

________________________________________________________________________________________________________________________________________

General overview of the research method

The present analyses are essentially based on two dialects of Naxi, AS (for /ɑ̄ ʂə˞ /) and FK (for /fṿ ́ kʰō/); see [START_REF] Michailovsky | Syllabic inventory of a Western Naxi dialect, and correspondence with Joseph F. Rock's transcriptions[END_REF] and [START_REF] Michaud | Three extreme cases of neutralisation: nasality, retroflexion and liprounding in Naxi[END_REF] for details.

Unless otherwise stated, the utterances cited come from the AS dialect, which belongs to Western Naxi (on the division between Western and Eastern Naxi: He & Jiang 1985:104-116). First-hand data from other dialects are also adduced when they yield relevant evidence.

Production data were elicited from one main language consultant for each dialect: a list of 1,000 words; 800 sentences translated from Chinese; and narratives. These data were sifted for examples of syllable deletion and tonal changes; rephrasings were tested with the language consultant; and production and perception experiments involving more subjects (reported in detail below) were set up to confirm and complement the observations. To obtain a precise measurement of F 0 -and indications on voice quality, not reported here-, an electroglottographic signal was recorded throughout recording sessions.

2. Experiments on High-tone syllable reduction, establishing a difference between the /MH/ contour and the /LH/ contour

As the /LH/ and /MH/ contours are not distinguished in previous descriptions of Naxi (e.g. [START_REF] He | 纳西语简志 N xiyu Jia hi (A Brief Monography on the Naxi Language)[END_REF]: 15, 54, He Zhiwu 1987: 61), which only report one rising contour, it appeared necessary to provide evidence for the claim made here that they are distinct.

All the production data reported in this paper were elicited from the same language consultant, a native speaker of the AS dialect, aged 56 at the time of the recordings. He will be referred to hereafter as M4, the label assigned in the Naxi database collected over several field trips; this label allows for unambiguous reference. In the course of work sessions, M4 page 6

________________________________________________________________________________________________________________________________________ developed an awareness of the tonal change in utterances such as (2a-b, 3a-b) above. He indicated that there was no homophony between /LH/ and /MH/ sequences. His intuition alone is not sufficient to settle the issue, however. The experimental setup used for confirmation was the following: seven minimal pairs of M-and L-tone predicates (verbs and adjectives), such as: /ndzɯ̄/ 'eat', /ndzɯ̀/ 'sit', were recorded in randomised order in carrier sentences where they received a floating High tone from the following morpheme. These Mand L-tone predicates were interspersed with 13 other predicates so that the M-vs.-L pairs

would not be conspicuous. The list of recorded items is provided in the Appendix, together with an internet link to the original audio and electroglottographic data. Two different carrier sentences were used, ( 5) and ( 6), with a view to obtaining evidence on the hypothesised contrast in two different contexts.

( The conditional/topic / ́ sé/ carries a floating High tone-tentatively placed to the left of the syllable in the transcription used here-which attaches to the preceding syllable, i.e.

to the target syllable of the experiment; for details on this process, see Michaud (2006a) [START_REF] Ohala | The Production of Tone[END_REF]: 30-31, Ohala & Ewan 1973[START_REF] Sundberg | Maximum speed of pitch changes in singers and untrained subjects[END_REF]). The degree of lengthening is not considerable, however. The vowel /u/ is much shorter than the vowel of the group-final particle /sé/ and the sentence-final particle /lé/, which are lengthened to indicate intonational junctures:

vowel length, which is not phonemic in Naxi, is used extensively to signal intonational phrasing (Michaud 2005:41-84). The F 0 range in which the rising contour is realised appears to differ according to the lexical tone of the syllable: it is lower for /ʂù/ (figure 2; see also figure 1, which contains the same verb) than for /ʂū/ (figure 3).

Averaged F 0 curves for the syllables recorded within carrier sentence (5) are plotted in figure 4, which presents both the raw data and curves averaged under the technical computing environment MATLAB following a procedure described in [START_REF] Michaud | Final consonants and glottalization: new perspectives from Hanoi Vietnamese[END_REF]. Due 1 The /s/ of the conditional/topicaliser / ́sé/ in figure 2 is voiced throughout. This is frequently observed (Michaud 2005:365-367), due to the fact that function words are prosodically weaker than lexical words in Naxi (as in many other languages). This effect is not systematic: the same morpheme is less clearly voiced in figure 3. The same account holds for the realisation of the initial consonant of /sè/ in figure 6.

Perception data

Perception data were elicited to verify whether the difference between syllables with /LH/ and /MH/ contours is perceived by listeners. Five native speakers participated in the listening test. One of them was M4, the language consultant who had produced the utterances, and with whom the experimental setup had been discussed; the other four had no awareness of the purpose of the test. Forty-two sentences-twenty-one containing /LH/

Reduction of Low-t ne syllables r sults in a coalescent [ ]

L-tone syllable reduction will be presented before M-tone reduction because it is more frequent. Low-tone syllables were observed to reduce to [ə].

Reduction of Low-tone grammatical words to [ə]

The particle /tʰè/, which conveys 'static aspect' (Pinson 1998:103), frequently simplifies to [ə], a process already reported by Fu Maoji (1984:314). Fu's fieldwork dates back to the 1930s and 1940s; over half a century later, this morpheme shows no signs of simplifying further and becoming a floating Low tone.

My data show this pattern to extend to other grammatical words; by order of frequency: the copula /wɑ/, the perfective aspect particle /sè/, the ongoing aspect particle /nɯ̀/, and the final particle /lɑ/, which conveys invitation: 'Let's…'. Figure 5 shows spectrograms and F 0 tracings of two realisations of the same passage of a narrative (by the same speaker, M4), /ŋgi ̄.ŋgi ̄. nɯ̀.mē/, without syllable reduction in the first case (7a), and with reduction in the second (7b). The folk tale from which this sequence is excerpted was As is bound to be the case with examples taken from continuous speech, the two realisations that figure 5 aims to contrast do not provide an ideal illustration of the phenomenon of reduction: in (7b), the strong friction noise at the beginning of vowel [i] (which palatalises the initial /ŋ͡ g/ to [ɲɟ]) and the nonmodal phonation towards the end of the vowel tend to blur the movement of the formants in the course of the vowel, which is expected to provide evidence of the presence of a final schwa-target. The change from a level F 0 curve on /ŋgi ̄/ in (7a) to a falling contour in (7b) is likewise difficult to assess from figure 5, as the decrease in F 0 over the vowel /i/ in (7b) could in theory be put down to a gradual decrease towards an intonation-group-final low target on the final particle, i.e. a

mere interpolation between the level pitch targets of successive syllables, rather than the effect of a coalescent [ə]. (As the tale from which these passages are excerpted were recorded with a microphone only, the F 0 curves in figure 5 were not calculated from electroglottography as in the other figures, but from the audio, using the software PRAAT: In passage (8), the second syllable of the reduplicated word /kʰō kʰò/ simplified to [ə].

The non-reduced form was dictated during the transcription session, the two informants consulted being unaware of the reduction.

Mid-tone syllables

Reduction of M-tone syllables in continuous speech is similar to L-tone syllable reduction in that it does not result in de-linking of the lexical tone. The only counterexample observed is presented in section 3.2.2.

Categorical reduction of /i / before final particles results in Mid-tone reassociation

There is one example where reduction of a Mid-tone syllable does result in M-tone reassociation: the reduction of the particle /i / when it precedes utterance-final particles. The resulting tone sequences are /HM/, lengthened M, and /LM/ after H, M and L tones, respectively. In Naxi, the particle /i / punctuates colloquial speech. In the AS dialect, it is almost systematically present, in the form of a floating Mid tone, before some final particles such as /mv̩ ́ sɯ̄/ (conjecture), /mɑ̀ / (certainty, strong affirmation), /tsɯ́ nɯ́/ (hearsay, indirect knowledge), /tsō wɑ̀ pɑ/ (conjecture, call for confirmation), /nɯ̄ wā/ (surprise), /lɑ/ (interrogation, call for confirmation), /mɤ̀ lɑ/ (pressing call for confirmation), /mē/ (emphasis), /mɤ/ (affirmation). Most language consultants are unaware of the underlying syllable; its identity was arrived at by substitution tests.

It appears noteworthy that M-tone floating is confined to this very restricted context, and that the vowel involved is /i/. Following the reviewers' recommendation, discussion of these facts is deferred until a later publication.

page 14 ________________________________________________________________________________________________________________________________________

Perception data on the recognition of reduced Low-and Mid-tone syllables

A test was performed with six listeners to evaluate the recoverability of the syllable having undergone reduction. In a first task, 14 utterances containing Low-and Mid-tone syllable reduction were played through loudspeakers, and the hearers were asked to repeat each utterance carefully. Their performance was written down by the author. In a second task, the identity of the syllable was verified by playing again the stimuli, proposing that an underlying syllable was present, and suggesting several candidates.

It appeared that the language consultants' awareness of the Mid-and Low-tone syllables having undergone syllable reduction varies from item to item, as is also the case for High-tone syllables having undergone reduction, described in Michaud 2006a. In the cases where a coalescent, tone-bearing schwa now systematically accompanies a certain word-typically final particles-, the identity of the underlying syllable could not be indicated by the majority of speakers. Indeed, no extra syllable was felt to be present: when asked to repeat carefully, they brought out the [ə] very clearly, and emphasised the melodic movement, but did not split the words into two syllables. Conversely, in the cases of free variation-e.g. ( 8) above, where the reduplicated word /kʰō kʰò/ becomes /kʰō ə/-, language consultants perceive the underlying syllable vividly, so much so that they are not aware that only a reduced form is pronounced, and dictate the full form during transcription sessions. Lastly, in some cases, a stylistic difference has crept in between full form and reduced form, and paraphrases have to be elicited before the underlying syllable can be arrived at and finally confirmed by the speakers. The experiment reported here aims to quantify the changes in F 0 that result from Ltone syllable reduction. Speaker M4-recall that he is the speaker who produced the data for all the experiments-recorded 27 monosyllabic predicates (verbs or adjectives) within the following carrier sentences:

(11) tʰɯ̄ TARGET SYLL. sè mē.

3 rd sg.

(TARGET SYLL.) perfect aspect particle final particle ( 12) tʰɯ̄ TARGET SYLL. ə̀ mē.

(as above; with p fect a p ct parti le in its r duced form)

If the target syllable is a verb, both ( 11) and ( 12) mean that the person referred to by the pronoun has performed the action referred to by the verb: '(S)he has ___ed.' If the target syllable is an adjective, these sentences mean '(S)he has become ___'.

The corpus is the same as for utterances (5) and ( 6) above. It was intended to select H-M-L series such as: /ndzɯ́/ 'fell (a tree)', /ndzɯ̄/ 'eat', /ndzɯ̀/ 'sit', but such a minimal set could not be found in every case. The predicates were arranged in random order. The speaker was aware that the focus of the experiment was on the reduction of the aspect particle /sè/. He was instructed to produce each sentence once at a slow pace, as if repeating for someone who was hard of hearing (thus eliciting carrier sentence 11), then repeat it more casually (eliciting carrier sentence 12). A translation of the predicate into the local dialect of Chinese was used as a prompt.

The effect of reduction of the following syllable on the target syllable is illustrated by figure 6, which shows the realisation of the verb /ndó/ 'to climb' in carrier sentences (11) and ( 12). [ INSERT FIGURE 6 HERE] In both cases, F 0 decreases in the course of the vowel /o/; however, the decrease starts earlier and is greater when the syllable is in frame (12), i.e.

page 16

________________________________________________________________________________________________________________________________________ when the following syllable is reduced. As for formant frequencies, when /sè/ is fully realised (top of figure 6), the only formant movement observed is a rise in F2, which is an effect of the following alveolar consonant (a similar movement is observable at the beginning of the vowel, after the alveolar initial /n͡ d/), whereas in the case when /sè/ has undergone reduction and coalescence with /ndó/ (bottom of figure 6), F1 increases from about 380 Hz to about 520 Hz in the course of the vowel, and F2 from about 850 Hz to about 1480 Hz, approaching the theoretical locus of schwa, namely F1≈ 500, F2≈ 1,500, F3≈ 2,500. For refined measurements, theoretical formant values of schwa may be calculated for a given speaker; a study of tongue movement for reduced vowels in English concludes that schwa has a target position, which corresponds to the mean of the positions for all the full vowels of the system [START_REF] Browman | Targetless' schwa: an articulatory analysis[END_REF][START_REF] Barry | Comments on Browman and Goldstein: ' 'Targetless' schwa: an articulatory analysis[END_REF]. and 9 HERE] From figure 7, it is clear that tone H becomes falling when followed by a reduced L-tone syllable. By contrast, the results for tones M and L (in figures 8 and 9) do not show any clear change in F 0 ; this small-scale experiment alone is not a sufficient basis to settle the issue whether the phonetic output of such /LL/ and /ML/ sequences are identical with /L/ and /M/, respectively. It appears reasonable to think that the underlying additional L tone does have some effect on F 0 but that it is less salient than the effect on vowel quality.

Production data on Mid-tone syllable reduction

The production task designed to investigate the effects of Mid-tone syllable reduction was based on the following carrier sentence: Slot A was filled by an adjective, and slot B by a final particle. Twenty-five adjectives were selected: see the Appendix for the list of items and an internet link to the original recordings. Sixteen particles were used, eight of which carry an accompanying floating Mid tone whereas the other seven do not have a floating tone. All the combinations were recorded (384 tokens in all; each token was said twice), in three separate recording sessions.

The adjectives were arranged in randomised order; the 25 were elicited in succession (their Chinese equivalent being used as a prompt) with the same final particle, which was indicated to the speaker in Naxi before the beginning of the series. The speaker (again, M4)

was not aware that the experiment focused on syllable reduction. The results of F 0 measurements show that the /HM/ and /LM/ contour tones have a straightforward phonetic implementation. They also suggest that the realisation of a /MM/ tone sequence is identical to that of a simple M tone, in the same way as /HH/ sequences were shown to be identical to /H/. The slight difference in length can hardly be significant, in view of the variation in length across items; the overall tendency for the /LM/ sequences to be longer can be explained in light of physiological factors, raising F 0 requiring more time than lowering it, as was already mentioned in section 2.1. suggests so. Straightforward experimental evidence could not be obtained because no plausible 'minimal pairs' of utterances could be found to contrast these contours. The AS and NL language consultants were asked whether the /lɑ/ + /sè/ ('strike' plus perfect aspect) and /lɑ/ + /jɤ/ ('strike' plus particle indicating direct observation) sequences 'sound exactly the same or not' after reduction of the second syllable; their intuition is that the contour is not the same, and impressionistic listening likewise suggests that there is a difference, though it may not be realised and perceived in all cases, its functional load being very light.

Conclusions

Conclusions concerning tonal contours in Naxi

The experiments can be taken to settle the first issue raised in the introduction, that of rising contours in Naxi: the /LH/ contour and the /MH/ contour are actually distinct.

Sequences made up of a Mid or Low lexical tone followed by a High tone (either delinked or floating) are realised as different dynamic F 0 shapes which transparently show the tautosyllabic realisation of the High target after the Low or Mid tone. There is no separate realisation of the floating High after a lexical High.

________________________________________________________________________________________________________________________________________

Mid-and Low-tone morphemes can reduce to [ə] and [ə], respectively, and coalesce with the preceding syllable. Said differently, sequences made up of a High, Mid or Low tone followed by a Mid or Low can also be realised on a single syllable, as before, but this syllable acquires a schwa offglide. Thus, in Naxi, syllable-reduction patterns are asymmetrical: High-tone syllable reduction leads to tonal delinking and reassociation, whereas Mid-or Low-tone syllable reduction stops short of complete tonal delinking.

Possible explanations of these processes, in light of universal phonetic tendencies and of language-specific factors, are being actively pursued.

On the typological validity of the notion of floating tone

As mentioned in the Introduction, phenomena of tone reassociation are now commonly modelled in terms of association lines between a tonal tier and a syllabic tier. This analysis applies, beyond the languages for which it was originally devised (essentially Niger-Congo languages), to the lexical tones of many languages. The present results go to show that the notions of floating tone and tonal reassociation are also applicable to Naxi. The present research aims to contribute data for the comparison of Far Eastern and Subsaharan tone systems-a line of research which is only in its incipient stage now.

Appendix: audio and electroglottographic data, and software for electroglottographic analysis The file names are as follows: 'Naxi_tones_' + number of sentence in main text + AUD for audio, EGG for electroglottographic files. For instance, Naxi_tones_4_AUD.wav is the audio file for example 4.

The list of items recorded in carrier sentences ( 5), ( 6), ( 11) and ( 12 In order to illustrate the difference between final discourse particles with and without a floating M tone, two recordings are provided: (i) one with final particle /mē/-conveying obviousn ss-, which carries a floating Mid tone that attaches to the syllable to its left; (ii) one with final particle /sjɤ/-used when the speaker was an eye witness to what (s)he reports-, which does not have such a floating tone. One single repetition is provided for each item.

  priest forward fetch (lexical form: /ʂù/)+added High tone come ... and [they] invited the priest to come along...

  figure, it is clear that a High tonal target is present, as predicted by the autosegmental tonal model. The /LH/ and /MH/ sequences are rising, without exception, whereas the /HH/ sequences are realised as a gently decreasing curve, similar to that of syllables with a simple H tones. (No experiment was set up to verify that the phonetic output of /H/ and /HH/ is actually identical.) The raw curves are not smooth due to the fact that they were obtained, not by autocorrelation, but by detection of each of the peaks indicative of glottis-closureinstants, on the derivative of the electroglottographic signal; this yields a precise estimation of the length of each glottal cycle, but no condition is placed on the continuity of the values from one cycle to the next (cf.Henrich et al. 2004 and references therein). The software that we developed is available online, with some documentation: see Appendix.The curves corresponding to /LH/ and /MH/ are clearly different, though final values are close. The final High target is perturbed in the expected direction by assimilation to the preceding tone, L or M. The results for the items in carrier sentence (6) are similar.

  Measurement of the downward tilt in F 0 resulting from L-tone syllable reduction

Figure 7

 7 Figure 7 provides average F 0 curves for the H tone, also plotting the other two tones as they appear in (11), taken as reference. The standard deviation is shown only for the two realisations of the High tones, which the figure aims to contrast. [INSERT FIGURES 7, 8

Figure 10

 10 Figure10presents F 0 curves averaged over the first 50 syllables in the series whose final particle is accompanied by a floating M tone.[INSERT FIGURES 10 AND 11 HERE]

  Figure 10 can be compared to figure 11, which shows the same adjectives, also in carrier frame (15), with one of the final particles that is not accompanied by a floating M tone. In figure 11, the Low tone is phonetically falling, contrasting with its rise in figure 10. The High tone is falling in both page 18 ________________________________________________________________________________________________________________________________________ cases, but the final downward tilt in figure 11 differs clearly from the steady fall in figure 10. An issue which remains open: the difference among falling contours Experiment 1 gave some experimental evidence for the difference between /LH/ and /MH/ tone contours. One may wonder whether /HL/ tone contours are likewise categorically different from /HM/ contours. Comparison of the production data in figure 7 and figure 10

  Naxi presents some cases of creation of new lexical items from the coalescence of two syllables: the first with Mid or Low tone, the second with High tone. This is phonetically unsurprising: syllable-initial vowels have a potential for coalescence with the preceding Further evidence for an asymmetry in the tone system comes from the comparison of two dialects: in AS, the final particle cluster /mv̩ ́ sɯ̄/ (which indicates conjecture) simplified to / śɯ̄/; in the dialect of /ndɑ̄ lè/ (丽江, 金山乡, 贵峰大来行政下村 /大来二村), following the inversion of all /H+M/ sequences on lexical items to /M+H/, this same particle cluster became /mv̩ ̄ sɯ́/, then simplified to /sɯ́/, the Mid-tone syllable disappearing without trace.It seemed interesting to gather further synchronic evidence on this issue. The results below show that, in contrast to High-tone syllables, Mid-and Low-tone syllables only reduce to [ə] and [ə], not to a Mid and Low tone, respectively-with one exception, presented in section 3.2.2.

	page 9
	________________________________________________________________________________________________________________________________________
	3. Experiments on Mid-and Low-tone syllable reduction
	This section investigates Mid-and Low-tone syllable reduction. With one illuminating
	exception (presented in section 3.2.2), these reductions respectively result in [ə] and [ə], not
	in de-linking of the tone: deletion of the segments is not complete.
	aspect particle /sè/ can simplify to /bɤ/; the tone of the resulting form is simply a Low tone,
	not a contour tone. The /HM/ pattern is illustrated by 'money': the conservative form (AS)
	is /ki ́.jɤ/, the coalescent form /kjɤ/ (old town of Lijiang), without any trace of the M tone.

contours, twenty-one /MH/ contours, inside frame 5-were played once in random order through loudspeakers; the listeners were instructed to provide a translation into Chinese for each. The intended syllable was recognised in 204 cases out of 210. This warrants the conclusion that the /LH/ vs. /MH/ distinction exists. vowel, as they have a soft onset: they begin by a semi-vowel in isolation, and link with the preceding syllable rhyme in connected speech. For example, 'mung bean jelly', a local dish, is called /hɯ̄.á/ in AS and other dialects outside the town of Lijiang, whereas the word has simplified to a monosyllable in the dialect of the old town of Lijiang 丽江 (a.k.a. Dayanzhen dialect 大研镇): /hà /, carrying a rising contour tone. There is apparently a single lexical contour tone, which we transcribe as /LH/, thus yielding /hà / and not /hā /; this fact was not verified experimentally. The resulting vowel-in this case, /a/-is identical to a simple vowel, i.e. the simplification to a monosyllable does not create new vowel phonemes.

No parallel creation of falling contours is observed: in cases of coalescence, /ML/ sequences simplify to /L/, /HM/ sequences simplify to /H/; no examples of lexical items coming from H+L were observed. For example, 'pickles' is /kjā.à/ in AS and other dialects outside Lijiang, /kjà/ in Lijiang. Likewise, the verb /bɯ̄/ 'go' in association with the perfect Comparison of tables 1 and 2 brings out the discrepancy between lexical and phrasal syllable-reduction patterns. [INSERT TABLES 1 AND 2 HERE] o e ə

  from memory at a four-day interval; the phrasing of this passage is similar in both cases, but in the second recording (7b), the ongoing aspect particle /nɯ̀/ simplifies to [ə] and coalesces phonetically with the preceding syllable.

	(7a) … li l ̄ɑ̄ há (…)	ŋgi ̄ ŋgi ̄	nɯ̀	m ē…
	'good old grandfather Li' walk (reduplicated)	ongoing aspect	particle
	'…good old grandfather Li was taking a stroll…' (from a narrative)
	(7b) ...	ŋgi ̄ ŋgi ̄	ə̀	m ē…
	(same glosses as above; particle /nɯ̀/ reduces to /ə/)
	[INSERT FIGURE 5 HERE]

page 11 ________________________________________________________________________________________________________________________________________ told twice

  The audio and electroglottographic (EGG) signals were simultaneously recorded into stereo files (audio in one channel, EGG in the other); as this format may not be convenient for all users, each stereo file was split into two: one audio file (name ending in _AUD.wav), one EGG file (name ending in _EGG.wav). There is no EGG recording for examples 7a and 7b.

	page 20
	1. Audio and electroglottographic data
	Part of the recordings on which this research is based are available online from the address
	below:
	http://halshs.archives-ouvertes.fr/hal-00144485

________________________________________________________________________________________________________________________________________

  ) is as follows (in the order Doublets were removed from the sound files. Item 17 is missing from the recordings in frame 5, items 24 to 26 from the recordings in frame 6, and items 8, 24 and 25 from the recordings in frames 11 and 12.The list of items recorded in carrier sentence (13) is as follows (in the order of recording):Due to restrictions of the vocabulary list available, this set is not phonemically or tonally balanced (10 L tones, 8 M tones, 7 H tones).

				page 21 page 22
	________________________________________________________________________________________________________________________________________ ________________________________________________________________________________________________________________________________________
	17 11	pʰū ʂə˞ ̀	to open long	开 长
	18 12	tsʰý mú	to compensate for old	赔偿 老
	19 13	ʂū mbū	to get back, to collect back 收(收回来) bright 亮
	20 14	pʰù ʈʂʰù	to scamper off rapid; of knife: sharp	逃跑 快
	21 15	ndzɯ́ ʂɯ́	to fell new	(用斧子) 砍 新
	22 16	ʈʂʰù ɳɖʐɯ́	rapid; of knife: sharp beautiful	快 美
	23 17	ɯ̄ ʂɯ̀	good, skilled yellow	好(技术好) 黄
	24 18	bē bȳ	to do coarse	做,干 粗
	of recording): 25 19	hɯ̄ ỳ	to go (past tense) light (not heavy)	去 轻
	number of item phonemic transcription English translation 26 tʰɑ́ apt, good 20 tsʰā hot	Chinese translation 可以 热
	1 27 21	ndə˞ ̀ tsʰɯ̀ ndzà	to call out loud to arrive annoying; homophone:	喊 到达 讨厌(同音词:花)
	2	ʈʂʰū	to read aloud colourful	读
	3 22	ndv̩ hó	to graze (cattle) deep	放牧 深
	4 23	ndzɯ̀ ndò	to sit stupid	坐 愚蠢
	5 24	ʈʂʰú mbē	to insert, to pierce shallow	插 浅
	6 number of item phonemic transcription English translation ʂù to look for 25 ŋgjɤ̀ difficult	寻找 Chinese translation 困难
	7 1	pʰý lɑ́	to vomit thick	吐 厚
	8 2	ndɯ̄ ndzɑ̄	to come dark	来 阴
	9 3	ndə˞ ́ pɑ̀	to measure broad	量 宽
	10 4	ɯ̀ gv̩	to grind good (e.g. good-hearted)	磨 好
	11 5	mé pv̩	to teach dry	教 干
	12 6	ndzɯ̄ mí	to eat ripe, cooked	吃 熟
	13 7	kʰá sī	to shoot (an arrow…) poor	射 穷
	14 8	ndə˞ ̄ mbì	to hit (the mark) thin, watery	中 (射中) 稀
	15 9	ndó ʂʷə˞ ́	to fall full	跌倒 满
	16 10	ndɯ̀ də˞ ̄	to plow tender, soft	犁 嫩

The software developed in collaboration with other researchers for the analysis of the electroglottographic signal (under the computing environment MATLAB) is available from http://voiceresearch.free.fr/egg/

Acknowledgments

Many thanks to David Bradley, François Dell, John Esling, Guillaume Jacques, Larry Hyman, Randy LaPolla, Martine Mazaudon, Boyd Michailovsky, David Mortensen, Annie Rialland, Jackson T.-S. Sun, Jacqueline Vaissière, and to Philip Rose and an anonymous reviewer for very helpful comments and suggestions. Many thanks to researchers in China for their friendly cooperation: Guo Dalie 郭大烈, Huang Xing 黄行, Kong Jiangping 孔江平, Xu Lin † 徐琳, and to the Naxi language consultants and friends, in particular He Xixian 和希贤 and Mu Ruhua 木汝华. The authors alone are responsible for remaining shortcomings.

Financial support was given by the Fondation de France and by Université P ris 3. Professional recording equipment was lent by the Laboratoire de Ph nétique et Phonologie (CNRS-LPP) and the Laboratoire Langues et Civilisations à Tradition Orale (CNRS-LACITO).