What Defines Language Dominance in Bilinguals?

This article focuses on the construct of language dominance in bilinguals and the ways in which this construct has been operationalized. Language dominance is often seen as relative proficiency in two languages, but it can also be analyzed in terms of language use-that is, how frequently bilinguals use their languages and how these are divided across domains. Assessing language dominance is important because it has become clear that the level of bilinguals' proficiency in each language and the relative strength of each language affect performance on tasks. A key distinction is made between direct measures of language dominance, which assess an aspect of language proficiency (e.g., vocabulary or grammar), and indirect ones, which measure variability in exposure to different languages and bilinguals' use of them. The article includes an evaluation of the extent to which the latter can be interpreted as a proxy for the former.