The role of linguistic context and language similarity in the relationship between language exposure and languageproficiency in bilingual children

Amount of exposure has consistently been shown to influence language development in bilingual children. To date, it has been treated as a variable that affects language development in the same way in different groups of bilingual children, but insights from several fields suggest that the similarity between languages and the context in which they are acquired may play a modulating role. This study therefore investigated the relationship between amount of exposure and language proficiency in different groups of bilingual children, varying in language similarity (Dutch–German vs. Dutch–French) and linguistic context (societal vs. heritage language). We found that language similarity affected the amount of exposure needed to reach a certain level of proficiency. Linguistic context had an effect too, although not for all languages tested. Overall, this study contributes to a more nuanced understanding of how amount of exposure shapes language development in bilingual children.