Author: Dr. Richard Steele

Aphasia in bilingual individuals is an area of growing importance to speech-language pathologists (SLPs) in the United States, according to a 2008 ASHA article by Lorenzen and Murray. Not only is the incidence of aphasia rising steadily — with prevalence projected to double over the next decade — but at the same time the number of bilingual Americans is growing. In the 2000 census, some 47 million persons over age five reported speaking a language other than English at home: English-Spanish bilingualism is most frequent, but sizable numbers of residents speak English as well as Chinese, French, or other languages. Feeding this growth in bilingual populations are both increases in family sizes and the arrival of new immigrants. As a consequence of these and additional factors, SLPs can expect to encounter ever-increasing numbers of bilingual clients with aphasia in their future caseloads.

Meeting the rehabilitation needs of bilingual clients with aphasia raises numerous challenging issues for SLPs:
• Assessing speech, language, and communication deficits in each of the languages
• Determining language-specific rehabilitation wants and needs of individual clients
• Understanding the contexts and purposes of different language uses
• Setting treatment goals appropriately
• Providing services effectively
• Identifying, understanding, and documenting improvements

Since a patient’s aphasic deficits frequently vary in different languages, language-specific responses to therapy can follow divergent paths, and the different languages can interact during treatment. As a result, the communication rehabilitation of bilingual persons is complex and not fully understood.
But while bilingual speech therapy presents fundamental challenges, it also provides important opportunities. Careful studies of rehabilitation in bilingual individuals with aphasia, for example, are helping us to refine our understanding of two crucial, basic issues: (1) whether different languages are represented in the same areas of the brain, and if not, then how; and (2) whether age of language acquisition in bilingualism influences the ways in which the languages are represented in the brain and how they interact. These are questions both of fundamental scientific import and of practical clinical significance. As we improve our understanding of these issues and are better able to characterize bilingual individuals with aphasia, then clinical personnel will be able to better assess deficits, determine needs, provide therapy, understand responses, and follow up after discharge.

Clinical studies to date have provided very preliminary answers. Different languages appear to draw on partially distinct, yet largely overlapping cerebral areas. As a consequence, overall aphasic severity may differ somewhat from language to language and two languages’ subsystems – such as their syntax or lexicon – may be affected somewhat differently. Age of acquisition also appears to influence how languages interact in bilingual individuals. A second language acquired in adulthood may be influenced by the speaker’s first language ¯ resulting, for example, in a foreign accent or unusual word usage ¯ in ways not observed in individuals whose two languages were both acquired during childhood. But work is still at an early stage, and much remains to be done to understand these phenomena in depth. Improved understandings of bilingual aphasia and its clinical management are matters of growing importance, both theoretically and clinically.
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For further reading: Bonnie Lorenzen, Laura Murray. “Bilingual aphasia: A theoretical and clinical review.” American Journal of Speech-Language Pathology, August 2008, vol. 17, no. 8, pp. 299–317.
doi: 10.1044/1058-0360(2008/026)

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