Exposure and input in bilingual development

Abstract

A growing literature on bilingual development explores relationships between language exposure and learning outcomes. Vocabulary size and pace of grammar learning have been claimed to be causally related to amounts or types of exposure to each language. Strong claims are made about the role of exposure on bilingual outcomes. Some researchers posit a unique learning result: a ‘weak language’. In a critical review, I voice reasons for scepticism that quantity or quality of exposure alone will explain findings. Central constructs are not well defined; inappropriate research methods have been used; the right kind of data is not discussed. Crucially, authors prevaricate on the notion of language itself, switching between cognitive and environmental perspectives. Both are needed to interpret bilingual behaviours but play different roles in the construction of learner grammars.