Bilingual aphasia: Explanations in population encoding

Abstract The study of bilingual aphasia has particular power to determine the neural basis of language function and can advance the treatment of aphasia. No theory of bilingual language has provided a coherent and comprehensive account for research results. I begin with a precis of a population encoding model of language function that assumes that representations are based upon the patterns of activity of large populations of neurons. I then consider how regularities in specific domains of language function (e.g. in semantics and phonologic sequence knowledge), frequency effects, and age of acquisition effects (strongest in lexical-semantics) might account for observed behavior in polyglots with aphasia. Finally, I review the literature on bilingual aphasia and its treatment to determine how well these hypotheses account for observed behavior. This analysis reveals that the population encoding theory can provide a coherent and granular account for this behavior.