Expressive vocabulary of German-English bilingual toddlers

This study investigated whether young children learning two languages simultaneously are inherently weaker language learners than their monolingual counterparts. Two questions were examined: (a) whether simultaneous language learning at an early age slows down the language learning process for both languages (bilingualism deficit hypothesis) and (b) whether young children use a unitary language system containing features of both languages, preventing them from separating the languages (unitary language system hypothesis). To test these hypotheses, vocabulary skills of 10 German-English bilingual toddlers were compared with those of monolingual German and English-speaking peers around 24 months of age using Rescorla's (1989) Language Development Survey. This vocabulary checklist, based on parental report, was used in its original English and in a German translated version. Findings revealed that bilingual toddlers were not inferior in conceptual vocabulary size and verb diversity when words in both languages were pooled. Given that nearly half of the bilingual conceptual vocabulary (43%) was associated with lexical forms in both languages, it is inferred that language separation is possible at age 2. Findings from this study contribute to the growing body of evidence that early simultaneous acquisition of more that one language is not an inherent disadvantage for the child. These findings suggest further that some existing instruments may be useful for assessing the early vocabulary of German-English bilingual toddlers.