ABSTRACT
Although bilingualism is common it has received relatively little attention in cognitive neuropsychological research. Perhaps this has been in part because a body of research on cognitive processing in normal bilinguals has only recently begun to accumulate, and also because research on both bilingual aphasia and cognitive processing has, until recently, been dominated by a question with a narrow focus. For bilingual aphasia, the question has been differential localization (see below), and for cognitive processing, the question has been whether the two languages are stored in a single or in separate representations. These questions focus on a narrow set of issues that restrict the scope of the emerging models. In this chapter we review the evidence in each of these areas and then examine how recent research on normal bilingualism can be productively applied to the study of bilingual aphasia. Concomitantly, we attempt to demonstrate how research on bilingual aphasia can contribute to the development of better-articulated models of normal bilingual cognitive processing. We will also attempt to show that the presence of more than one language in a single cognitive system raises some questions that could not otherwise be posed, and that the answers to these questions will provide important constraints in the search for the neural substrates of cognitive performance. Finally, to demonstrate these points we will end with a Case Illustration to provide an example of how our suggestions could be implemented in future investigations of bilingual aphasia.
