The term bilingual aphasia is used to refer to aphasia in persons who speak two or more languages. When a multilingual speaker has aphasia following a stroke, the languages spoken premorbidly may show comparable or differential patterns of impairment. Differential patterns may manifest as greater impairment in one language compared to another, or as differences in the characteristics of aphasia. Clinical reports of bilingual aphasia show dissociations in the processing of the language learned first (L1) and and second (L2), with one language more impaired than the other. Other cases show a pattern of differential recovery where L2 is recovered only after L1. Another pattern is alternating antagonism; i.e., patients access one language in spontaneous speech and inhibit the other language for alternating periods. This term should be used for a type of aphasia in a person who speaks multiple languages in which the impairment is different for different languages. [from
HPO]