Argument structure processing in bilinguals and bilingual speakers with aphasia: A cross-linguistic investigation

Abstract

Previous research has shown that costs associated with verb argument structure processing scale with the number of arguments and/or as a result of non-canonical argument mapping. Increased difficulty associated with these factors has also been reported for persons with aphasia (PWA). Basque assigns ergative case to subjects of unergative and transitive, but not unaccusative, verbs. The present thesis studies how these case assignment patterns affect processing costs required for unergative, unaccusative and transitive verbs in Basque in contrast to Spanish and English. In three experiments, the performance of neurotypical Basque-Spanish bilinguals and bilingual PWA is tested via tasks targeting lexical-, sentence- and connected-speech levels of linguistic representation in both production and comprehension. Distinct behavioral measures are used to evaluate cross-linguistic patterns of argument structure processing. Our results in neurotypical Basque speakers indicate that ergative-case markings significantly affect the processing cost of unergative verbs. In contrast, Spanish showed patterns consistent with English, i.e., unaccusatives elicited increased processing cost when compared to other studied verb groups. With respect to the PWA, the Spanish-English bilingual PWA manifested intensified but qualitatively similar argument complexity effects to those in neurotypical speakers. The performance of the Basque-Spanish PWA goes against our predictions for Basque and Spanish. Overall, the present thesis brings novel evidence that languages with ergative-absolutive case alignment, like Basque, do not pattern alike with more commonly studied nominative-accusative languages like Spanish or English in terms of argument structure complexity effects, calling for further cross-linguistic investigation. We endorse cross-linguistic research on argument structure processing, especially in understudied languages like Basque, and stress the need and importance of a cross-linguistic approach to aphasia.