Why dialogue matters in aphasia

Abstract Aphasia is commonly described as impairment of an individual language system. This article asks what happens to dialogue when the linguistic resources used to accomplish social action are disrupted. Drawing on Weigand’s language-as-dialogue theory and Mixed Game Model, together with dialogical linguistics, conversation analysis, multimodal interaction and functional communication, it argues that impairment is necessary but insufficient to explain aphasic performance. Dialogue is the organisation through which impaired and preserved resources become consequential for initiative, reaction, repair and understanding under particular partner and activity conditions. The account distinguishes individual linguistic capacity, competence-in-performance, dyadic accomplishment and participation, and shows how aphasia sharpens dialogue theory under communicative asymmetry.