Agrammatic speakers of languages with overt grammatical case show impaired use of the morphological cues to establish theta-role relations in sentences presented in non-canonical word orders. We analysed the effect of word order on the sentence comprehension of aphasic speakers of Basque, an ergative, free word order and head-final (SOV) language. Ergative languages such as Basque establish a one-to-one mapping of the thematic role and the case marker. We collected behavioural and gaze-fixation data while agrammatic speakers performed a picture-matching task with auditorily presented sentences with different word orders. We found that people with aphasia (PWA) had difficulties in assigning theta-roles in Theme-Agent order. This result is in line with processing accounts. Contrary to previous findings, our data do not suggest a systematic delay in the integration of morphological information in the PWA group, but strong reliance on the ergative case morphology and difficulties assigning thematic roles into the determiner phrases.

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Background: Comprehension of non-canonical sentences is frequently characterised by chance level performance in people with aphasia (PWA). Chance level performance has been interpreted as guessing, but online data does not support this rendering. It is still not clear whether the incorrect sentence processing is guided by the compensatory strategies that PWA might employ to overcome linguistic difficulties. Aims: We aim to study to what extent people with non-fluent aphasia are aware of their sentence comprehension deficits. Methods & Procedures: This study combined offline and online data to investigate the effect of word order and error-awareness on sentence comprehension in a group of PWA and non-brain damaged (NBD) participants. The offline tasks involved auditory sentence picture-matching immediately followed by a confidence rating (CR). Participants were asked to judge the perceived correctness of their previous answer. Online data consisted of eye-tracking. Outcomes & Results: Replicating previous findings, PWA had significantly worse comprehension of Theme-Agent order compared to Agent-Theme order sentences. Controls showed ceiling level sentence comprehension. CR was a poor predictor of response accuracy in PWA, but moderate-good in NBD. A total of 6.8% of judgements were classified as "guessing" by PWA. Post hoc gaze data analysis indicated that CR was a predictor of the fixation pattern during the presentation of the linguistic stimuli. Conclusions: Results suggest that PWA were mostly unaware of their sentence comprehension errors and did not consciously employ strategies to compensate for their difficulties.

Experimental research on argument structure has reported mixed results regarding the processing of unaccusative and unergative predicates. Using eye tracking in the visual world paradigm, this study seeks to fill a gap in the literature by presenting new evidence of the processing distinction between agent and theme subjects. We considered two hypotheses. First, the Unaccusative Hypothesis states that unaccusative (theme) subjects involve a more complex syntactic representation than unergative (agent) subjects. It predicts a delayed reactivation of unaccusative subjects compared to unergatives after the presentation of the verb. Second, the Agent First Hypothesis states that the first ambiguous NP of a sentence will preferably be interpreted as an agent due to an attentional preference to agents over themes. It predicts a larger reactivation of agent subjects than themes. We monitored the time course of gaze fixations of 44 native speakers across a visual display while processing sentences with unaccusative, unergative and transitive verbs. One of the pictures in the visual display was semantically related to the sentential subject. We analyzed fixation patterns in three different time frames: the verb frame, the post-verb frame, and the global post-verbal frame. Results indicated that sentential subjects across the three conditions were significantly activated when participants heard the verb; this is compatible with observing a post-verbal reactivation effect. Time course and magnitude of the gaze-fixation patterns are fully compatible with the predictions made by the Agent First Hypothesis. Thus, we report new evidence for (a) a processing distinction between unaccusative and unergative predicates in sentence comprehension, and (b) an attentional preference towards agents over themes, reflected by a larger reactivation effect in agent subjects.