Introduction

One of the most intriguing aspects of bilingualism which has increasingly come to interest researchers is the question of how a bilingual's languages are organized and processed psycholinguistically. In exploring this question, one major approach has been to analyze the pathological speech produced by bilingual aphasics, on the assumption that the types of linguistic breakdown observed there have important implications for how healthy language is organized and processed.

Case studies of bilingual aphasics have documented differential patterns of loss and recovery for each language – along with the more frequent case where both languages are affected in a like manner. Examples of language mixing in the aphasic have also been reported. Data of this type have been used to formulate neuro- and psycholinguistic models of bilingual system interaction (for reviews, see Paradis, 1983, 1977, and Albert and Obler, 1978).

In addition to bilingual aphasia, other neurological pathologies may also be used to elucidate the psycholinguistic functioning of bilinguals. Informal observations from demented bilingual speakers show that their linguistic and communicative behavior in each language may be differently affected in ways similar to that of aphasics. Specifically the demented bilingual may exhibit difficulties in choosing the appropriate language for the monolingual interlocutor, or upholding one language throughout the interaction.