Effects of Bilingualism on Language Acquisition: A Comparative Study

This project aims at assessing the effects of bilingualism on language acquisition, comparing successive bilingual and monolingual learners in child language development and foreign language acquisition. We focus on grammatical knowledge which is acquired late in monolingual language acquisition, specifically aspects of morpho-phonological and semantic knowledge. Earlier research in early bilingualism and child second language acquisition has ignored such late-acquired grammatical knowledge.

We assume that acquisitional differences between bilingual and monolingual learners are related to the development of the bilingual lexicon. It is hypothesised that during the early stages of bilingualism, when the lexicon is being shaped into a bilingual storage system, additional cognitive effort on the part of the learner causes a temporary delay in lexical development, slowing down acquisition of lexical-grammatical knowledge. However, once it has matured, bilingual lexical organisation gives bilingual learners cognitive advantages over monolingual learners, particularly for foreign language acquisition. We hypothesise that the size of effects caused by the development of a bilingual lexicon strongly depends on the type of grammatical knowledge which is acquired, correlating with the degree of lexical conditioning. Accordingly, the programme aims at answering the following questions concerning the effects of bilingualism:

1. How does the development of L1 lexical-grammatical knowledge differ in monolingual versus successive bilingual child learners of Dutch?
   
2. How does the development of L2 lexical-grammatical knowledge differ in monolingual versus successive bilingual teenage learners of English as a foreign language?
   

These questions will be addressed for two linguistic areas: morpho-phonological constraints on inflection, and lexical-semantic constraints on sentence interpretation. Research strategies will be proposed to assess the contribution of bilingualism as a global factor, cancelling out effects of influence of native language grammatical knowledge on target language grammatical knowledge. The programme's results will provide a fine-grained picture of the global effect of bilingualism on language acquisition.

Part I: The Semantics Subproject

        The semantic sub-project examines phenomena in which fine-grained lexical features (i.e. features more specific than syntactic category) systematically constrain or license interpretive mechanisms. As a control, closely related nonlexical grammatical constraints are examined.

Part II: The Morpho-Phonology Subproject

Assuming a dual mechanism model of morphology, late-acquired inflections in English and Dutch are a valid testing ground for our hypotheses since they instantiate two types of grammatical knowledge: rules and lexical storage. We predict a correlation between degree of lexical storage and delayed acquisition by bilinguals.