Selective Sentence Production Deficit in an Agrammatic Yoruba-English Bilingual Patient with Minor Stroke: A Case Study

Abstract

Speech helps us to communicate with our loved ones and significant others through construction of grammatically coherent sentences that are comprehensible to our communication partners. As such, impairment of this ability as a result of stroke can be debilitating and disabling to the patients as well as significant others. Agrammatism is deficit in the use and processing of grammatically coherent syntactic structures following damage to the Broca's complex or region. Most studies have traditionally emphasized monolingual patients, with bilingualism now receiving increased attention. However, few studies have specifically investigated the effect of minor stroke on agrammatic bilingual individuals. This study examined an agrammatic Yoruba-English bilingual patient with minor stroke with a view to describing their sentence production (deficit). The findings strongly support the existence of distinct language-specific lexical-subsystem centres in the Broca's complex for native and acquired languages (Yoruba-English) whereas both languages are likely connected to a single semantic system in the anterior temporal lobe and its surrounding regions. Furthermore, acquired language is more susceptible to brain damage than native language. This might imply that severity of deficit in speech production in both native and acquired language of bilingual aphasics may be determined by the size of lesion in the Broca's complex or region.