Early nouns in bilingual acquisition : a test of the separate development hypothesis

In previous work (Sinka & Schelletter 1998), we have addressed the morphosyntactic development of two bilingual children and the issues raised by the opposition between the Single System and the Separate Development hypotheses. Interactions between the two language systems were found to be very rare, consistent with the Separate Development Hypothesis. This is further underlined by the developmental lead-lag pattern evidenced in the emergence of Functional Categories (Schelletter, Sinka & Garman 1999, Garman, Schelletter & Sinka 1999). More recently (Sinka, Garman & Schelletter 2000), we have supplemented our investigation of early grammatical development by using a lexical profiling approach to focus on the evidence from the acquisition of main verbs. Results suggest that the lead-lag order of development for the two languages in each child is the same as for the grammatical system, and each bilingual child appears to be developing the system of main verbs independently for each language, although there are some commonalities across languages, e.g. in the development of the verb 'to be'. In this paper we extend the lexical profiling approach to the analysis of noun vocabulary. We look at the general characteristics of types and tokens, and then consider more fine-grained analysis of the nouns used by each child in terms of grammatico-semantic categories. The findings will be discussed in relation to the Separate Development Hypothesis.