Although the methodologies for describing many types of linguistic variation have been well developed, satisfactory theoretical links between data and explanation – especially links that include causal mechanisms – remain lacking. This article argues, somewhat paradoxically, that even though most choices reflect some societal pattern, speakers make linguistic choices as individuals. That is, choices ultimately lie with the individual and are rationally based. Rational Choice Models (e.g. Elster 1979, 1989, 1997) provide explanatory mechanisms for the ways actors in society select from alternative structures and available options. The Rational Choice approach taken here is enhanced by diverse theories of human action (e.g. Damasio 1996, Klein 1998, Lessig 1995). Analysis of codeswitching examples within a recasting of the Markedness Model (Myers-Scotton, e.g. 1993, 1998) suggests how a rationally based model offers better explanations for linguistic variation than do other approaches.

This study investigates morphological vulnerability in incomplete bilingual L1 acquisition. It examines the production of L1 inflections by L2-dominant bilingual children, with the aim of exploring causes of difficulty in agreement marking. Spontaneous data (18 hours) from six Hungarian-English bilingual children, aged seven to nine, is used to compare the production of possessive inflections and verbal inflections, which are expressed by identical surface morphology in Hungarian. Drawing on recent analysis of Hungarian (Alberti, 1995;Szabolcsi, 1994), the paper asks where and why agreement morphology is susceptible to variability in bilingual children's weaker L1. Results indicate significant differences in the accuracy of agreement morphology. Inflections are almost error-free in possessive nominals and subject-verb agreement. However, they are frequently omitted in possessive be-clauses, which can be attributed to a combination of factors: (i) influence of semantic-syntactic properties of English have on Hungarian be possessive construction (transfer from L2); (ii) difficulty with long-distance agreement in Hungarian be-possessives (structural complexity of L1); and (iii) influence of Hungarian existential and locative constructions on possessive-be (ambiguity in L1). It is argued that morphological variability is selective, and the main source of vulnerability is the syntax-semantics interface where the weaker L1 is most susceptible to L2 influence.

Link to this article: http://journals.cambridge.org/abstract_S1366728910000295How to cite this article: RAKESH M. BHATT and AGNES BOLONYAI (2011). Code-switching and the optimal grammar of bilingual language use.In this article, we provide a framework of bilingual grammar that offers a theoretical understanding of the socio-cognitive bases of code-switching in terms of five general principles that, individually or through interaction with each other, explain how and why specific instances of code-switching arise. We provide cross-linguistic empirical evidence to claim that these general sociolinguistic principles, stated as socio-cognitive constraints on code-switching, characterize multi-linguistic competence in so far as they are able to show how "local" functions of code-switching arise as specific instantiations of these "global" principles, or (products of) their interactions.* We would like to express our special thanks and gratitude to the anonymous reviewers for their insightful suggestions and constructive comments. We also thank the editors for their assistance. We are particularly grateful to Carmen Silva-Corvalán for her invaluable advice and continued support. Ewa Jaworska deserves special thanks for her copy-editing work. We would also like to acknowledge Tímea Kovács for her assistance with the transcription of the Hungarian-English data. The authors are listed in alphabetical order.

This paper examines structural consequences of intensive language contact on simultaneous L1 and L2 child language development in an L2-dominant environment. Based on the assumption that structural processes in language contact are operating at and determined by abstract complex lexical structure, various structural configurations in bilingual speech (e.g., codeswitching, convergence, and a Composite Matrix Language) are explained in terms of three levels of abstract lexical structure: the lexical-conceptual structure, predicate-argument structure, and morphological realization patterns. Empirical evidence from Hungarian/English bilingual speech demonstrates that as a result of a turnover in the Matrix Language abstract lexical structure can be “split” and “recombined” in such a way that surface structure is projected by an underlying grammatical system which is a composite. Prevalent changes and patterns of linguistic structure are interpreted in relation to ongoing language shift to L2, or L1 maintenance/attrition.

This paper investigates how and what properties of abstract lexical entries in the mental lexicon interact with the distribution of surface morphemes in language contact and/or L1 attrition. Data from Hungarian/English bilingual children provide evidence that asymmetries in the production of Hungarian preverbs and case suffixes may be explained by considering how these morphemes are elected in language production. Effects of differential election and status of “early” versus "late” system morphemes interact with effects of cross-linguistic incongruence and result in different patterns of error types in the use of preverbs and case suffixes. The results of the study support the predictions of the 4-M model and the Abstract Level model (Myers-Scotton & Jake, 2000). Working within the framework of the 4-M model and the Abstract Level model provides a principled explanation for interrelations between language production and the morphemic organization of the bilingual mental lexicon.