Processing argument structure in mild, non-fluent aphasia: Preliminary findings from contrasting Spanish with Basque and English

PURPOSE: People with aphasia have been found to experience more difficulty in producing verbs with a greater number of arguments (transitives vs. intransitives) or non-canonical argument mapping (unaccusatives vs. unergatives). Basque is an ergative-absolutive language that assigns ergative case marking to subjects of unergative and transitive but not unaccusative verbs. We hypothesised that Basque would lead to different patterns of verb retrieval difficulties in people with aphasia than Spanish and English. METHOD: Two bilingual people with aphasia (P1: Spanish-English; P2: Basque-Spanish) were tested in both their languages on three verb groups (unergatives, unaccusatives, and transitives) in tasks targeting production of single words, sentences, and connected speech. Verb retrieval errors were compared across verb groups, and proportions of produced verbs were calculated. RESULT: In both languages, P1 exhibited higher error rates for unaccusatives (Spanish: 4%, English: 10%) compared to unergatives (Spanish: 2%, English: 2%) and transitives (Spanish: 3%, English: 4%). P2 showed higher error rates on transitives (Basque: 8%, Spanish: 5%) than on unergatives (Basque: 2%, Spanish: 4%) and unaccusatives (Basque: 7%, Spanish: 3%). CONCLUSION: Although the findings suggest potential cross-linguistic differences in processing, the contribution of ergative case marking to verb production difficulties remains unclear and warrants further investigation.