2Chapter 3 An Approach to Differentiating Bilingualism and Language Impairment
Bilingualism presents a weighty challenge to clinical assessment in general and to the analysis of language impairment (LI) and neurological disorders in particular. A wide range of linguistic and social phenomena converge in the bilingual person in ways that are often difcult to differentiate. Simply analyzing and comparing the two languages of a bilingual may be insufcient for determining impairment or identifying disorder (although this alone would be a major improvement of much current practice that generally addresses only a single language, often, the second language). From a research perspective, clinical disorders offer numerous challenges to the study of bilingualism, in particular: what it means theoretically to know a language, the notion of completeness in linguistic knowledge, and the relationship between a language user’s two languages. From a practitioner’s point of view, theory and method in bilingualism can help inform clinical decisions that may make a large difference in people’s lives.