Exceptional bilingualism

New proposals for rethinking the concept of modularity have prompted researchers to increasingly consider the findings from outside their respective fields. A recent discussion by Marcus (2006) calls for such a multidisciplinary reflection. This paper reviews recent research from the field of bilingualism with a special focus on exceptional circumstances of learning and acquisition (deafness, language impairment, and literacy disorder). Findings from this work bear directly on the new approach to modularity that is being proposed. Both exceptionality and bilingualism allow for perspectives on cognitive architecture that may reveal how its components are structured and how they interact in a way that is not as easy to assess in typical language ability and monolingualism. The critical issues appear to be separability (autonomy) of neurophysiological systems, and whether or not cognitive structures are subserved by domain-specific or domain-general substrates. Resolving these questions will have important implications for the remediation of developmental disorders in language and literacy, and for a better understanding of the development of sign language and spoken language-based systems in deaf children.