eds. Höder Kühl

Katja Ploog
email: katja.ploog@univ-orleans.fr

When language resists. From divergence to language dynamics: A review article of Stability and divergence in language contact: Factors and Mechanisms (Braunmüller and

Keywords: Language dynamics, activity, variation, change, contact, divergence, convergence, stability 1. When language resists

The volume Stability and divergence in language contact: Factors and Mechanisms edited by Braunmüller and Höder and Kühl (2014) contains eleven studies about divergence and/or stability in language contact. The contributions plead for a differential description of language development (variation, change, stability) insofar as a given contact phenomenon makes sense in a different way from various perspectives. As convergence/divergence represent more/less structural harmony between languages in contact, the deeper sense of internal and external motivations (factors, mechanisms) of these dynamics is discussed. We argue that the key entity of development is the speaker, who takes the active part in the structuring process by a in-process positioning in discourse and the long-scale elaboration of his repertoire.

If convergence is that process of "making languages more similar" (Clyne, 2003: 79) or, as a result, "partial similarities increasing at the expense of differences" (Weinreich 1954:395), a "decrease in similarity between dialects, which amounts to linguistic diversification, growing diffuseness and heterogenization" (Hinskens,SDLC: 111) can be called divergence. From the definition on, divergence goes together with convergence; The latter is assumed to be the default case of evolution in language contact situations.

Actually, language contact does not evidently mean evolution, and divergence is not necessarily the contrary of convergence. Consequently, divergence is a fundamental issue about language change that is worth investigating. The aim of the volume edited by Kurt Braunmüller, Steffen Höder and Karoline Kühl is to work out when and why languages in contact do not converge. Stability and divergence in language contact: Factors and Mechanisms (SDLC from now on) gives a rich sample of cases that make understand convergence and divergence in a more general perspective of (dynamic) language ecologies. The book follows up on the 2011 Hamburg symposium about convergence and divergence in language contact situations; a first colloquium was organized by the researchers in 2007 within the same topic domain. A lot of work had been done previously by the European Science Foundation network "The convergence and divergence of dialects in a Changing Europe" (1995)(1996)(1997)(1998) under the responsability of Peter Auer and Frans Hinskens (Auer et al. (eds.) 2005).

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The theoretical part of SDLC is somehow preliminary insofar as it contains solely two contributions provided by the editors, the first one in form of a taxonomy of scenarios that extract elements from problematics illustrated by the following articles (Kühl and Braunmüller), the second by presenting his own model of structural developement (Höder). Kühl and Braunmüller ("Linguistic stability and divergence: An extended perspective on language contact", SDLC: 13-38) propose a classification of types of language development focussing on divergence and stability, based on various contact situations of Germanic languages. The basic claim of the authors is to attribute different scenarios to complex configurations of internal, external and extralinguistic factors and mechanisms of the speaker's (bilingual) language practice. Höder ("Convergence versus divergence from a diasystematic perspective", SDLC: 39-62) argues that the default case of convergence consists actually in "pro-diasystematic change", that is, in the development of languageunspecific structures within a unique constructional system including the languages in contact. Höder illustrates this process with examples from the contact of Low/High German in Northern Germany, where the dynamics nowadays favour the emergence of a dialectal North High German.

The empirical part offers a wide range of approaches, although the majority of the studies refer to variationist framework (especially Hinskens; Villena-Ponsoda and Ávila-Muñoz; Sollid and Conzett and Johansen; Sandøy and Anderson and Doublet). The studies represent, in the editors' words, a wide range of (actually mostly Germanic and Romance) languages.

Dialect contact is the main topic (Berg; Hinskens; Aalberse and Moro; Tsiplakou; Sollid and Conzett and Johansen; Villena-Ponsoda and Ávila-Muñoz; Sandøy and Anderson and Doublet), complemented by contact situations between historically and geographically closely related languges such as Spanish and Portugese (Döhla). Contact with other linguistic groups in boundary areas is illustrated in a contribution about Northern Norway (Finno-Ugric languages) and the question of diaspora dialects is discussed in two contributions from the Netherlands (Hinskens; Aalberse and Moro) and in Fischer and Gabriel and Kireva's article about Judeo-Spanish in Bulgaria. Articles show an interest in all structural levels of language, from (morpho-) phonological variation (Hinskens, Sandøy and Anderson and Doublet, Villena-Ponsoda and Ávila-Muñoz) to grammatical evolution in argument-marking (Berg, Döhla) word order (Fischer and Gabriel and Kireva), and nominal and verbal flexion (Tsiplakou, Aalberse and Moro, Sollid and Conzett and Johansen). Several articles analyze structural features in terms of linguistic attitude (Tsiplakou, Villena-Ponsoda and Ávila-Muñoz, Döhla). On the whole, the topics discussed give a very stimulating insight into contact linguistics issues; the reader simply would have appreciated a more evident ordering of the contributions that make up this part: fact that Judeo-Spanish has never had a second-language learner group (i.e. there is a low dynamics of simplification).

Hinskens ("Despite or because of intensive contact: Internal, external and extralinguistic aspects of divergence in modern dialects and ethnolects of Dutch through two different types of hyperdialectalization", SDLC: 109-140) displays studies of six (closely related) dialects of Dutch in order to establish a hierarchy of divergence factors. He focusses on two cases of hyperdialectalization, one concerning the case when native speakers emphasize structural particularities of their dialect as a claim to differential identity, the other one as a process taking place within second-language acquisition by Dutch bilingual speakers with an immigration background (i.e. "faulty analysis" of target variety: Hinskens, SDLC: 114).

Aalberse and Moro ("Stability in Chinese and Malay heritage languages as a source of divergence", SDLC: 141-162) emphasize cases of structural stability of the heritage language in bilingual practice of diaspora speakers from Mandarin and Ambon Malay in the Netherlands. A comparison of nominal and verbal modification resources shows that the heritage variety is less dynamic than the homeland one and, for that reason, is described as more stable. Apart from internal factors such as paradigm regularity (obligatoriness, predictability) -and in this sense, simplification -the major factor of stability pointed out by the authors is communication ergonomics through reduced input/output, acquisition order, conditions of practice.

Tsiplakou ("Does convergence generate stability? The case of Cypriot Greek koiné", SDLC: 163-178) argues that the apparent convergence of Cypriot Greek and Standard Modern Greek results in a relative stability (i.e. maintenance of the diglossic situation between standard and dialects, as far as this convergence is 1) restricted to the most salient structural level that is morpho-phonology (fully taught at school), and 2) partial, in the sense that the speaker's discourse remains heterogeneous. The purpose is introduced through a corpus extract that convincingly illustrates the complex interplay of language attitude and code mixing in Cypriot Greek.

Sollid and Conzett and Johansen ("Gender and noun inflection: the fate of 'vulnerable' categories in Northern Norwegian", SDLC: 179-206) take a close look at the hypothesis that Norwegian noun inflection a nd gender distinction are undergoing strong simplification in the northern part of the country as a convergence with the local Finno-Ugrian languages Sámi and Kven. The authors argue that the hypothesis does not hold facing the diversity of local practice: The stability of the gender system is explained by typological salience of the feature in addition to norm pressure and dialect divergence in both noun inflection and gender by the distinctiveness of sociolinguistic configuration, i.e. long time contact and multilingualism on the coast of Nord Troms, and a rather diglossic contact with shift in the inland areas.

Villena-Ponsoda and Ávila-Muñoz ("Dialect stability and divergence in southern Spain: social and personal motivations", SDLC: 207-238) discuss the interplay of sociolinguistic stratification and small-scale variables in the divergence of two major Spanish dialects of Andalusia. The authors support a challenging fieldwork method combining sociolinguistic correlation and network on three levels of analysis in order to show that, apart from the persistence of vernacular tendencies within the whole of Andalusia, eastern and western varieties of higher-class speakers tend to underline local identities as far as they are following the urban models of, respectively, Madrid and Sevilla.

Sandøy and Anderson and Doublet ("The Bergen dialect splits in two", SDLC: 239-264) report diversification of urban dialects in Bergen, after a levelling process documented in the 1970's. No specific factor has yet been identified to neatly explain the divergence process between Fana and Bergen (center), though the two parts of the municipality have distinctive social identities as a result of the massive influx of economically favoured inhabitants of Bergen to Fana during the last few decades. According to the authors, prestigious variants continue to develop in Fana while Bergen continues to reinforces low variants as a "neighbour-opposition". This dialect split seems to signify that the social stratification of dialects has changed into geographically identified sociolects. Döhla's contribution ("Diachronic divergence and convergence in differential object marking between Spanish and Portuguese", SDLC: 265-290) illustrates how the inverse dynamics of convergence and divergence can apply to the same structural phenomenon successively: In Portuguese, DOM kept on developing until the 17th century under the pressure of the prestige of Spanish in a context of generalized bilingualism. From the 18th century on, national ideology has led to the establishment of a Portuguese national identity and language. Nowadays, DOM has totally disappeared from Portuguese, but keeps developing continuously in Spanish.

Divergence and the dynamics of language contact

Convergence/divergence has been a central subject matter in language science since its very beginnings. Initiated by Schleicher and promoted by Comparative Grammar in the 19th century, the tree model represents genetic relationships between languages or language families and the progressive, historical divergence between languages from the same root or mother language. The pioneer concept of convergence in linguistics was outlined by Schuchardt (1919Schuchardt ( -1921)), inspired by psychology and mathematics: Schuchardt claimed that the nature of language evolution was not only a historico-genetic one but also an "essential" kinship due to the function of language in human life; more explicitly, Schuchardt qualified language as an activity (Thätigkeit). Admitting that contact -i.e. heterogeneity of resources -is the basic situation of language practice, Schuchardt showed that convergence was a central aspect of language evolution. [START_REF] Weinreich | Languages in contact[END_REF] introduced contact-induced change as a main topic in modern linguistics. His inaugural work about Languages in contact identifies the speaker as the "locus" of contact who is, as such, the central generator of convergence/divergence phenomena.

Actually, system is an external category that can be traced back to the linguist's model, but that is not necessarily the way the speaker conceptualizes language structure. Contemporary research in contact linguistics is concerned with the articulation of structuring scales speech and language. Three main perspectives are adopted in this area:

1) Issues about the constellation of factors for contact-induced development. Renewing the biological metaphor, the concept of ecology has been suggested [START_REF] Haugen | The ecology of language[END_REF][START_REF] Calvet | Pour une écologie des langues du monde[END_REF][START_REF] Mufwene | The Ecology of Language Evolution[END_REF]) to explain the complexity of language dynamics through the processes of competition and selection, constrained by factors of language use. [START_REF] Thomason | Language contact: an introduction[END_REF] discusses sociolinguistic conditions of diffusion of contact-induced innovations and concludes that there is an intertwining of interactional and social factors. [START_REF] Grosjean | The bilingual's language modes[END_REF] establishes different speaking modes following the relative activation of each language of the repertory. Modes are determined by a punctual constellation of extralinguistic factors such as competence, attitudes, situational features and semiotic environment.

2) Issues about structural consequences of langage contact. As a facilitation of language production, interlingual identification has cognitive (psycholinguistic) causes. [START_REF] Poplack | Sometimes I'll start a sentence in english y termino en español[END_REF]Poplack ( , 1998) ) and [START_REF] Myers-Scotton | Duelling languages. Grammatical Structure in Code-Switching[END_REF], 1995) modelize constraints of co-articulation of the systems in bilingual speech through levels of morpho-syntactic integration. Two major outcomes of language contact can be distinguished, related to the kind of practice of the L2 that is undergoing change: on the one hand, imperfect learning of a second language likely results in shift induced change; on the other, borrowing is typical of bilingual practices where L2 competence is less critical, i.e. in contact situations where speakers have less need to become involved or where they have good proficiency.

Modalities of interlingual identification have been a central topic in contact linguistics starting from Weinreich:

"Inasmuch as a language is a system of oppositions, a partial identification of the systems is to the bilingual a reduction of his linguistic burden. and it is these natural identifications which are at the root of many forms of interference." (Weinreich 1967: 7) Rather than transfer, interlingual identification means (con)fusion of elements from distinct language systems, and interferences are, in a sense, abusive identifications. From a similar point of view, [START_REF] Clyne | Dynamics of Language Contact. English and Immigrant Languages[END_REF] describes the convergence and transference complex to be an individual dynamics: if convergence is the process of connecting two or more languages in use, divergence appears to be a secondary stage as it means to avoid convergence. Clyne (2003:142ss.) argues that this can be done best through the integration of the exogenous element into structure. In this sense, divergence is proportional to integration, determined through type, degree and stability. [START_REF] Johanson | The dynamics of code-copying in language encounters[END_REF] outlines three major types of contactinduced mechanisms depending on the question whether it is the weak (A) or the strong (B) code that gives the impetus for transference. The outcome is supposed to be a more or less hybrid copy. [START_REF] Ross | Calquing and Metatypy[END_REF] suggests the concept of metatypy for massive typological convergence (advergence). Most authors agree with the point that we are dealing with language restructuring (change) when a contact-induced structural innovation is used by a monolingual speaker; the controversy is about the possibility to trace back the innovation to one of the contact languages.

3) Issues about the more-dimensional creative process of innovation. But the very distinction between internal/external/extralinguistic factors of language change disregards the speaker as an active part of language change. To the extent that pattern replication can be analyzed as language-internal grammaticalization that is triggered by a construction in the contact language, contact can be a central explicative factor for grammaticalization and, in this sense, causes change indirectly. In these approaches, the search for structural mechanisms meets with search for factors. The central factor of interplay of structural change and social setting seems to be best addressed by communicative conditions. Two conclusions from this survey: Firstly, recent research around convergence/divergence aims to investigate language contact as a complex phenomenon and to understand it through a speaker oriented, small-scale model of language. Secondly, both convergence and divergence take place in large-scale time processes through several steps and under a complex constellation of factors. In all, a dynamic model of language would understand convergence and divergence as permanent reorganization dynamics of more or less heterogeneous language resources in speech activity.

Going ahead: describing categories

Stability is when nothing happens?

One strong point of the volume is to show that convergence and divergence are, rather than opposites, relational concepts that offer complementary viewpoints of language variation and change: neither one exists as such and a stated phenomenon refers to convergence and to divergence and to stability, depending on the token perspective.

In most cases, the relationship between convergence and divergence may be described as two faces of the same coin, as convergence may lead to divergence and vice versa. (Braunmüller and Kühl,SDLC: 14) If convergence and divergence are "diachronic processes and results that increase or decrease intersystemic similarities in language contact situations", Braunmüller and Kühl "define stability as the stage when change no longer happens, or when it never occured" (SDLC: 14). In this sense, stability can be established before or after a period of development: what is the scale, i.e. is Portuguese case-marking stable or Brazilian practice divergent? What about regular, continuous change such as DOM in Spanish? Does ongoing development that does not suffer any destabilization (contrary to Portuguese DOM during the 17th and 18th centuries) mean stability? Then it would be wrong to state that during stability "nothing happens"…

The generalization of the demonstrative marker in heritage Malay (SDLC: Aalberse and Moro2 ) shows how system congruence between languages in contact can favour stability, through convergence between the heritage variety and the dominant language, more exactly, convergence of the heritage language to the dominant language, in the sense that it is influenced by the obligatory article category from Dutch. This case also means divergence from the homeland variety (where the demonstrative marker is pragmatically but not grammatically constrained). The point is that when divergence also means convergence, the dynamics described involves another supplementary language: we deal either with a double contact or with an original and a final state of development, or both. But it is not so obvious if this constellation has to be described as stability: from a systemic point of view, the predictability of the determiner represents a development, that is, strictly speaking, a complexification (grammaticalization) of the paradigm in Malay, but a simplification of interlinguistic correspondence. There is a similar problem with the interpretation of generalization of a unique sortal classifier (at the expense of more specific ones) in heritage Mandarin: In the sense that it is maintenance of functional divergence between Dutch and Mandarin, it appears somehow like stability; but to the extent that heritage Mandarin is not following the main course of Mandarin in general with the effect of simplification through reduction of the paradigm, there is not nothing happening. In both cases, the main outcome is a better predictability and less variability in discourse. From a dynamic point of view, this might better be called regularization than stability.

Actually, if speakers seek to lower the processing cost, convergence should improve stability, or lead to a more stable state of the language, at least in the case of convergence from dialect to standard (passive koineization, following [START_REF] Sobrero | Italianization and variation in the repertoire: The Koinai[END_REF]. Convergence of some parts of the system (morphology in both cases) to the standard may allow the local identity through an emerging new dialect that is a structural "compromise", which is illustrated in the SDLC volume by Berg and Tsiplakou, respectively from Northern High German and Cypriot Greek koiné. But divergent explanations are provided about this partial convergence. The development of Northern High German gives evidence to the more general hierarchy in evolution of German dialects, i.e. results in stability of an ongoing development. On the other hand, apparent (superficial?) convergence in the Cypriot case acts as a "robust 'buffer' against contact-induced de-dialectalization" (Tsiplakou, SDLC: 163) so far as overt (partial) convergence is covert resistance through code-mixing at the discourse level (accommodation), and, on the whole, results in a relative stability of the contact situation. The most relevant factor to this difference may be the social constellation of dialectal bilingualism: in Northern Germany, Low German is in rapid decline while the use of Cypriot

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Greek is generalized and remains unmarked in private and informal situations. Talking about stability or convergence remains a question of the viewpoint taken… Stability seems not so easy to deal with, except over the long-term time scale of languages. Despite some allusions to a dynamic view -such as Hinskens' suggestion that divergence and convergence have to be understood as epiphenomena of the more general processes of language development; indirectly, Aalberse and Moro give an illustration of stability as a process (literally actualized in the structural elaboration of discourse). But on the whole, this still retains a static conception of language: Most of the contributions do not outline what happens but what has happened.

Contact as a basic condition of language change?

A lot of reflection has been done so far into factors of language change, especially under contact. Hopper and Traugott (1993:63ss.) claim that the presence of two systems in a repertory is a major motivation for grammaticalization through syncretization of the systems in contact. In the words of [START_REF] Heine | Language contact and Grammatical Change[END_REF], grammaticalization can be understood as an imperfect replication. But if convergence appears to be a compensation strategy (Myers-Scotton 1993), the process of (imperfect) replication itself follows universal principles (Andersen 2001). In fact convergent tendencies can be independent and due to internal factors. Cases have been observed where geographic proximity does not explain convergent development between dialects, which seems to be best explicated as internally motivated (français zéro: [START_REF] Chaudenson | Vers une approche panlectale de la variation du français[END_REF], spread without diffusion: Andersen 1988).

The subtitle "Factors and Mechanisms" of the volume makes the reader hope for some more general reflection about components of the language development process. Braunmüller and Kühl (SDLC) list the following factors and mechanisms (parameters?) with influence on the outcome of language development: the locus of (individual/societal) multilingual practice; the (complex) constellation of intra-and extralinguistic factors; interlinguistic distance and possible equivalence coordinated with speaker proficiency; psycholinguistic factors such as processing costs; sociolinguistic attitudes; political and geographic factors; standardization and roofing language; intralinguistic divisions (styles, registers). From this, Braunmüller and Kühl (SDLC: 33) identify the following types of factors and mechanisms: language-internal (codification, register specification), individual (cognitive mechanisms, bilingualism), societal (features of network and community) and extralinguistic (geo-polical/economical) factors and mechanisms. At the end, it seems that the 1973 taxonomy of internal, external and extralinguistic factors worked out by Andersen has not so much developed. How do parts of a language become suitable to change? Under what conditions is the outcome divergence vs. convergence?

Interlingual distinctivity as a factor of development

Höder (SDLC) suggests an organization of linguistic knowledge in terms of translinguistic generalization and abstraction, where diasystematic links are established as far as possible. [START_REF] Clyne | Dynamics of Language Contact. English and Immigrant Languages[END_REF] cites cases of trilingual speaker interlingual identification that show that a feature shared by two of the languages is suitable to be extended to the third one. The general dynamics behind this development consists in generalizing the "majority" structure. Another typical process of trilingual convergence is to establish conversion rules based on markedness principles [START_REF] Henning | Markedness and the theory of linguistic change[END_REF][START_REF] Herwig | Plurilingual lexical organization: evidence from lexical processing in L1-L2-L3-L4 translation[END_REF][START_REF] Clyne | Dynamics of Language Contact. English and Immigrant Languages[END_REF].

A high genetic familiarity, i.e., a weak degree of typological difference between the involved languages seems to play a role in this process. Yet, on the one hand, the more similar two constructions/languages are, the higher the probability of convergence. A contact between typologically close languages favours convergence, because connections and compromises are easy to establish. The contact of dialects (in opposition to language contact, Trudgill 1996) per se favours convergence as the two systems present a high proportion of congruent structures -"divergence between closely related dialects seems to be the marked case" (Hinskens,SDLC: 109). On the other hand, the more different two constructions/languages are, the more useful (necessary?) convergence is: a main goal for the speaker would be to "keep the cognitive costs in language processing low" (Matras 2009:151) in languaging. Thus structure competition follows universal tendencies by giving advantage to ease of articulation, regularity of paradigms, obligatoriness, complexity and marking hierarchies in general.

When interlingual identification (Weinreich 1953:7) is not possible, convergence may be a successful strategy for harmonizing resources as it provides simplification for the speaker: "For multilingual speakers, the establishment of dia-constructions is a simplification of their linguistic knowledge, in the same way as the establishment of any type of (monolingual) abstract pattern is a simplification." (Höder,SDLC: 46) The example from Berg seems to show that convergence does not mean simplification as the dative case marking represents an additional functional value in the system. Actually this is only true when considering Low German separately: In a context of full proficiency of all speakers in High German, the complex bilingual competence can be supposed to be heavily influenced by High German structural features. Höder concludes in this sense that contactinduced change is first of all a change "within one multilingual system" (Höder, SDLC: 58) before being a change in a monolingual system in contact with another. Actually diasystematic links in the sense of Höder or [START_REF] Weinreich | Is a structural dialectology possible?[END_REF] are restricted to small parts of a system (subsystems, in a more essentialist point of view): language change is limited to some features while other features remain stable.

On the other hand, divergence implies that language features are strong enough to resist external influence or, even more, to entail interlingual distinctivity:

From the various studies discussed, whatever the type of variety and however narrow or wide the geographical perspective, there is converging evidence for the claim that (a) divergence often has external motivations which are usually 'boosted' by internal ones, and (b) social psychological forces presuppose internal and/or external motivations (Hinskens,SDLC: 136).

Divergence is regularly related to language attitudes. This proceeds from the fact that resistance to convergence such as in the case of hyperdialectalism (Hinskens) or neighbouropposition (Sandøy and Anderson and Doublet) must be sustained by strong motivation for the marking of linguistic difference and awareness of linguistic characteristics, related to societal factors such as language ideology, and in many cases, to language planning (deliberate change in terms of [START_REF] Thomason | Language contact: an introduction[END_REF].

The factor debate

The debate on internal and external factors resembles the ancient opposition of Schuchardt and the Neogrammarians, about psychological and physiological factors of change, contrasting genetic relationship and contact. But language science has somehow improved. The above considerations about processing cost (internal factors), attitude (extralinguistic) and communicative activity (external) all lead to the same point: the work of the speaker, and the relevance of a speaker-oriented model. From this perspective, we had better focus on processes than on results. 1) A rather casual handling of the very concepts of factor or mechanism in our field of contact linguistics has to be noticed. This has some strong epistemological tradition: for instance, [START_REF] Thomason | Language contact: an introduction[END_REF] gives a taxonomy of (extralinguistic, social) mechanisms in contactinduced change; but as this makes explicit the causes or the outcomes (shift, maintenance, bilingualism, language creation) of change, we would rather call them factors than mechanisms. This may be explained by the fact that both convergence and divergence can be understood as a process or as a result. Convergence as a state (including as a result of change) in other places is called congruence, e.g. the subtitle "Language Families, Typological Resemblance, and Perceived Similarity" of Besters-Dilger et al.'s (2014) book Congruence in Contact-induced Language Change. Braunmüller and Kühl (SDLC) put stability and divergence together as alternative outcomes (other than convergence) from a language contact situation; we notice that the purpose of divergence in their perspective is maintenance of existing divergences rather than reinforcement of differences (but cf. Hinskens' point about hyperdialectalism and Sandøy et al.'s about dialect split in Bergen). As a process, stability is "zero-development", the opposite of both instability and change, and can be considered as a topic in historical linguistics: what is the time scale needed to account for these processes? Can stability be measured in synchronic states of language through "survival" of old patterns (Fischer et al. about syntactic conservatism of Hungarian Judeo-Spanish)? Etc.

2) The controversy about internal and external/extralinguistic factors has been qualified as an "academic non issue" [START_REF] Heine | Language contact and Grammatical Change[END_REF] since all changes are multifactorial. It will be more relevant to rank factors, explicating "in which way and to what extent each of the two contributed to shaping grammatical change" (ibid.). Several authors from Heine to Matras and Andersen, identify among relevant factors a "creative behavior activated to use the linguistic resources available in novel ways" (Heine and Kuteva 2005:35). Creativeness is actually inherent in human language; we would consider it, rather than a "variable", as a prerequisite for replication, whose characteristics shape the structural outcome of the speakers' activity. In this sense, the principles of grammaticalization apply to replication. What is called external factors contains 'all about use', in sum, situations in which the languages are "competing" and communicative settings of language contact. These factors determine intensity and duration of contact, speech styles (casual vs. ritualized, bilingual…). As a result, language use constrains more internal parameters such as relevance of systemic homogeneity in communication, types of co-actualization, frequency of practice (routinization, pre-structured patterns, prediction), acquisition order, etc.

If linguistic dynamics deals inherently with internal factors and if, wherever language contact is actualized, it is determined by external/extralinguistic factors, the opposition of factor types does not benefit the understanding of language development itself.

The search for structural harmony

Braunmüller (SDLC) states that the relative frequency of studies about convergence is not proportional to what is happening in language contact situations (i.e., stability or even divergence are just less often under study than convergence). This runs against the wellshared assumption that convergence is default development in language contact situations: if this is the case, why are languages in contact supposed to reduce structural divergence? Distance between languages implies high processing cost for the bilingual speaker. Convergence diminishes this cost because it aims at better structural harmony between languages in contact. There seems to be a concrete added value of harmony in the social life of the speaker, in the form of loyalty or communicative efficiency (mobility), and a more abstract harmony, in the form of the structuring (categorization) of linguistic resources. This leads us to address convergence/divergence in context with social space and discursive mobility.

The speaker is not an external factor of language

The very distinction between internal/external/extralinguistic factors of language change neglects the speaker as an active part of change. Factors around the speaker are typically comprehended as external ones since they are related to use. But language itself is an external phenomenon insofar as language norms are social projections of structures that are individually memorized and, potentially, shared by a community, implicitly by ordinary speakers or explicitly by grammarians or linguists. And language is a static representation.

1) The process. Modern stands such as "contact at the interindividual level is a critical factor in almost any case of language evolution" (Mufwene 2001:137) take up Schuchardt's intuition that language contact dynamics is based on the activity of the speaker, that, for itself, can be traced back to the Humboldtian paradigm of speaker activity in developing the inner form of language. In some modern models internal and external factors are linked in one more-dimensional creative process: to the extent that pattern replication can be analyzed as language-internal grammaticalization that is triggered by a construction in the contact language -in other words, contact is the explicative factor for grammaticalization and, in this sense, causes the change indirectly [START_REF] Heine | Language contact and Grammatical Change[END_REF][START_REF] Matras | An activity-oriented approach to contact-induced language change[END_REF]. A few attempts have recently been made to distinguish different phases of propagation of innovative features. Implicitly, we might understand stability as a regular path of genesis.

2) Mechanisms. Contact-induced factors of language change are generally supposed to be external. [START_REF] Weinreich | Languages in contact[END_REF]: "the language-using individuals are thus the locus of contact" has been interpreted with respect to interference. Interference can be described, basically, as specific performance 'symptoms' of language competence. These 'symptoms' have been analyzed, especially for educational purposes and with reference to Vygotski, under the term of languaging [START_REF] Swain | Communicative competence: Some roles of comprehensible input and comprehensible output in its development[END_REF]. We would hypothesize that speaker and speaking conditions are directly responsible for structuring. If convergence/divergence can be described in terms of processes and mechanisms, relatively to the production of structure through a bilingual speaker, it must be the goal to understand the very emergence of structure in real time.

-Activation of languages in speech: Classic psycholinguistic models (especially [START_REF] Levelt | Speaking. From intention to articulation[END_REF] have been adapted to the practice of multilingual speakers. The question is how the involved language systems are activated -separately [START_REF] Grosjean | The bilingual's language modes[END_REF][START_REF] Myers-Scotton | Duelling languages. Grammatical Structure in Code-Switching[END_REF] or jointly (De Bot in Höder, SDLC) -in the speech production process. An intermediate position consists in modeling competence distinctively in local subsets, following the possibility (and usefulness) of correspondences. Code switching, for instance, is activated on the item level, so that there is no need to conceive simultaneously activated language systems that would weigh upon the performance. Speakers build their own cartography of microsystems via original relationships between structural features, diasystematic links in Höder's words. These links are, first of all, specific to the speaker and the discursive challenges they have to meet.

-Activity of construction: More than the features of the contact language itself the mere fact of contact induces specific communicative conditions. Reflection about convergence/ divergence process should deal with constraints on written/spoken practice. This issue is tackled in the SDLC volume solely in the context of methodological purpose of the contributions (cf. Tsiplakou, Aalberse and Moro, Berg, Döhla 3 ). It would be worth mentioning the sequential work of the speaker online. Acting under the pressure of time impacts on the construction project with regard to reference, finality, feedback from other speakers, etc. Precisely, constraints of immediate linearity affect the structuring via priming, i.e. activation of specific parts of the repertory in momentaneous speech.

-Structural input for building a competence: Nobody would deny that aspects of the social configuration are facilitators or inhibitors of the propagation of an innovation in speech. Jakobson (in Andersen 1988:60) observed that dialects which tend towards the role of koîné have simpler phonemic systems than dialects which serve a purely local function; McWorther (2007) argues that linguae francae are simplified languages to the extent that they have a high proportion of L2 speakers. But if it is true that complexity (simplicity, consistency) is directly related to frequency, (reduction of internal) complexity is only indirectly related to the contact. Practice reduced to specific situations determines the setting of styles and constructions in the repertoire; Scattered or infrequent practice prevents routinization (synthetic handling, anticipation in speech). A reduced input conditions gaps in competence.

The concept of mobility fits well to describe this ongoing structuring process on the speakers level. In any case it would be problematic to consider it as external.

Mobilities in language and discourse

Since linguistic contact (at the level of idiolect, dialect or language) takes place in the mind of individual speakers and there is no reason why the coexistent systems must be kept (neatly) apart, there is no particular reason why the "matériaux de construction" cannot have been selected from different sources initially for the purposes of establishing successful communication, with the unplanned result of producing a new language variety (Mufwene, 2001: 78).

-Language dynamics must deal with time scales. Most of the previous remarks consider small-scale time of actual discourse or mechanisms of (individual) structure elaboration. Parallel morphosyntactic constructions, various types of borrowing, congruent lexicalization [START_REF] Muysken | Bilingual Speech: A Typology of Code-Mixing[END_REF], grammatical simplifications (decrease in complexity: Sampson and Gil and Trudgill 2009) are "interlinguistic realignments" [START_REF] Braunmüller | Morphologische Komplexität des Deutschen im Vergleich mit den skandinavischen Sprachen -typologisch und sprachhistorisch[END_REF] or "interlingual shortcuts" (Besters-Dilger and Braunmüller 2014), etc. and organize the speaker's mobility. This means that convergence/divergence applies locally, while a lot in the languages stays unchanged.

Yet real time projection of constructions and storing in a longer run do not imply any change on the collective level or stabilization. Actually we should make clear how the individual restructuring spreads or diffuses in the community. Höder's model of diasystematic change, traced back to Weinreichs (1954) concept of diasystem, is very close to Matras' (2009) pivot matching: Pivot matching is based on lexical polysemy, which permits the speaker to establish correspondences between items through a common functional value, generally of a concrete nature. Other values are arranged around this pivot. Best syncretization then leads to adaptations (convergence). Now, Matras' pivot matching is initiated by a communicative finality emergent in a given interactional context relayed by a language act and finally by the elaboration of the most adequate concrete structure. This research draws from the whole repertoire.

The regular starting point of innovation is grammatical competence, but, clearly, not necessarily incomplete competence of a target grammar. [START_REF] Matras | Investigating the mechanisms of pattern replication in language convergence[END_REF] argue that the goal of convergence is to enlarge structural possibilities and, consequently, it is a process of extension of the functional scope of a pattern under contact conditions. The establishing of correspondences in heterogeneous resources implies, for the speaker, discursive mobility. Andersen's 1973 distinction between deductive and abductive change (proceeding from Peirce, in Morand 2004) provides a model for describing the language transmission process taking into account the speaker's grammar and discourse, but has received surprisingly little attention. Even though this parallel might irritate the author, his approach considerably problematizes the modern construction-grammatical framework: A speaker's discourse depends strictly on his grammar, but he may produce innovative features (spontaneous or adaptive), creatively from competing grammatical features; if they work well, they have a chance to be used more than once. Diffusion of a convergent/divergent structure takes place in transmission; distinctive interpretation of a given input (a feature perceived in discourse) from one generation to the next will lead to differences between grammars of the following generations. What is a discursive (deductive) innovation for the first-generation speakers then becomes (abductive) change in next-generation speakers grammar. As this internal grammar is not entirely determined by its discursive model, bifurcations are possible in competence building: "Any ambiguity in the observed discourse data which different learners may resolve differently is sufficient reason for an (abductive) innovation" (Andersen 1989:18). But ambiguity is not random: prior decisions determine possible innovation in competing alternatives in accordance with universal principles of grammar formation (f.i. markedness).

Ecology of speaking: space is not neutral

In the course of our argument, we moved away from convergence/divergence. This way, we confirmed Braunmüller and Kühl's claim that convergence/divergence are specific phenomena of a more general process of language development. A last step should be taken to return to the purpose of Stability and divergence in language contact: Factors and Mechanisms: we have seen that contact is the prevalent factor of language change and that convergence (the establishing of interlinguistic correpondances) is the unmarked case of change. Under what conditions do speaker renounce their mobility? Are divergence and stability forms of negative accommodation? The answer is in social space. It matters a lot if a convergence/divergence development takes place in a contact situation between languages in the same area or between languages within a given territory. The first attempt to relay linguistic phenomena on spatiality was Schmidt's (1872) theory of waves: In a given linguistic area, changes develop from central to peripheral areas. What has been called intercourse by Saussure (1995: 282) meant diverse forces at work in linguistic use that characterize dialects as dynamic (central) and conservative (peripherical). An esprit de clocher may favour centripetal forces that lead to the elaboration of local peculiarities. Both dynamics explain that a given territory is linguistically ordered. Distribution of languages in geographical and social space delineates the scenario setting of contact: territorialization of the languages in contact and functional specialization of varieties.

Languages in the same area may be genetically related or not, but the fact that languages are related to the same roofing language almost implies a conflicting situation for the speaker to manage. In the case of endogenous (≠ diaspora) dialect convergence/divergence, the languages are genetically related, politically related, and established in the same geographical area. As a major successor to dialectology, a variationist approach is predestined to take into account geographic variation in its modelization. Surprisingly, the SDLC volume does not dwell on settlement questions: some of the contributions lack a theoretical reflection about spatial distribution of dialects, others include this dimension although it is not the main purpose. This is certainly a question of focus, but it would be worth addressing at least two spatial stakes since they would help us to outline different types of language dynamics: in social space, the more a contact is intense, the more harmony is required (dialect contact in Cypriot Greek); on the other hand, disharmony becomes possible through geographical and/or social distance between communities (heritage/homeland varieties of Mandarin and Malay).

Esprit de clocher thinking is reinforced in Cyprus (island), Andalusia and the inland area of Northern Norway (peripheral), Dutch hyperdialectalism near to the German/Belgian border, etc. Urbanity favours density of social life where interlocutors tend to group and encourage speakers to create social subcategories, in order to assume social heterogeneity and to exist differentially; the attitude of an innovating community may be exocentric when establishing a hierarchy between national/regional urban centres, in addition to supplementary hierarchies such as urban centre vs. surroundings (Malaga and Sevilla) or spatial sub-entities within the urban space (Bergen and Tana); finally, the migrant dialects of Dutch discussed in SDLC are basically urban… Seen from the speaker's point of view, any language practice takes place in a socially ordered configuration of places of life: we conclude with [START_REF] Matras | An activity-oriented approach to contact-induced language change[END_REF] that the interplay of structural change (internal and external factors) and social setting (extralinguistic factors) seems to be best explained by communicative conditions:

Language contact phenomena are seen […] as the outcome of function-driven choices through which speakers license themselves, while interacting in a context of type B, to select a structure (word-form, construction, meaning, phonological features, and so on), despite its association primarily with interaction context set A. When claiming that choices are function-driven, I am not suggesting that selection of Astructures in B-contexts is necessarily always conscious, deliberate, or strategic. [...] All, however, are functional in the sense that they are the product of language processing in goal-oriented communicative interaction.

[…] contact-induced language change is a product of the propagation of creative innovations introduced by speakers as task-effective means to achieve communicative goals. The key to understanding the position of individual structures and structural categories in the process of contact-induced change is to interpret the role of those structures in triggering linguistic-mental processing operations that support specific communicative tasks (Matras, 2012: 22).

In short

Through a stimulating diversity of topic matters and case studies taken mainly from indoeuropean languages, the volume Stability and divergence in language contact: Factors and Mechanisms brings out that language dynamics is a complex phenomenon that can be described from various perspectives. Hence, convergence often goes hand in hand with divergence.

Convergence/divergence are those general processes that permit an efficient and expressive handling of linguistic resources, in actual use and in competence building. Change of social norms is a secondary product of these processes. Convergence is the default development of heterogeneous linguistic resources. For the speaker, convergence means mobility on the discursive level and can be described as a symptom of coordination devices in the structuring process of his repertoire. Divergence has a higher cognitive expense and is therefore supposed to be motivated, in a strong sense. The benefit of divergence in language use is identity work and sharpening of social boundaries. Stability does not exist as such, but characterizes a secondary process of convergence or divergence, as a continuously ongoing change or the (surprising) maintenance of differences. More than a discrete phenomenon, it is a qualitative feature of one of the two main processes.

I'm grateful to Catherine Paulin, Matthew Pires and Klaus Ploog for their precious help to improve this contribution. All errors remaining are my own responsability.

The starting point of the authors was to argue in opposition to the general hypothesis that heritage speaking implies attrition (and specifically loss of structural features / categories that are not congruent with the contact language), conformly to the distinction of a strong (dominant) and a weak (dominated) language.

Although Döhla deals with written data where linearity is not a major focus, the relevance of genre becomes explicit in his contribution.