Lemma congruence checking between languages as an organizing principle in intrasentential codeswitching

This paper studies intrasentential codeswitching (CS) phenomena at two levels of abstraction: the level of lexical-conceptual structure and the level of predicateargument structure. At the level of lexical-conceptual structure, language- specific semantic and pragmatic feature bundles are activated for the speaker's intentions; at the level of predicate-argument structure, morphosyntactic directions encoding the predicate-argument structure are activated. Lemmas are abstract entries containing semantic, syntactic, and morphological information in the mental lexicon. This paper argues that lemma congruence checking between languages involved in intrasentential CS at these two levels is a fundamental organizing principle governing intrasentential CS constructions. Without exploring the issues regarding the roles of lemma congruence between languages involved in intrasentential CS,any analysis of the phenomenon would remain at the descriptive, rather than explanatory, level. Based on naturally-occurring Chinese/English intrasentential CS instances, this paper explains why certain types of salient congruence between languages are necessary in order for intrasentential CS to occur and predicts what structural restrictions and consequences may occur as a result of insufficient congruence or incongruence at any of these two levels. Accordingly, it makes proposals about the nature and structural organization of mixed bilingual production.