The present study compares the use of morphological case for argument interpretation between German L1 speakers in Norway and Germany to investigate whether and how processing may be affected by attrition. Participants were presented with a spoken sentence and pictures of two scenes, one showing an event as described by a transitive or ditransitive sentence and another showing the same event, with the roles of agent and patient (transitives) or recipient and theme (ditransitives) reversed. Their task was to select the scene that matched the sentence. End-of-sentence responses show no between-group differences in comprehension. Moreover, eye movements show that both groups exploit case marking on the first noun phrase in transitive sentences in the same way. However, differences in processing between groups emerge for the use of case marking on the first object following a ditransitive verb. While the home country group shows a higher likelihood of looks to the target after a dative-marked article than after an accusative-marked article prior to the second object, the reverse holds for the expat group, at least temporarily. Altogether, the results indicate subtle changes in the processing of alternating argument orders in ditransitive sentences in L1 German, potentially as a result of the bi-/multilingual experience.
