The processing of compounds in bilingual aphasia: a multiple-case study.

Background: While converging evidence has led to the view that people with aphasia exploit compositional procedures when producing compound words, the issue of what compoundinternal characteristics are at play during these procedures is still under debate. It has been argued that constituent position and/or morphosyntactic prominence, i.e., being the head constituent of a compound, may influence the manner in which compounds are accessed. However, findings obtained from patient performances are thus far inconclusive, because positional and headedness effects are frequently confounded in a language. Aims: In order to disentangle position-in-the-string and headedness effects in compound production in aphasia, the main objective of this study is to investigate the performance of bilingual patients speaking languages in which these effects can be teased apart. Our secondary goal is to probe the roles of grammatical category (adjectives vs. nouns) and of between-language phonological similarity, as both these factors have been demonstrated to influence compound processing. Method & Procedure: Three English-French bilingual persons with aphasia participated in the study. Three experimental tasks, reading, repetition and translation of isolated compound words, were administrated in each language. We contrasted French and English compounds that differ in the position of the head constituent, left for French and right for English. Outcomes & Results: Two participants showed a similar pattern, a significantly reduced number of errors for the head (or first) constituent as compared to the non-head (or second) constituent in French and an equivalent number of errors for both constituents in English, pointing to the cumulative effects of headedness and first-position-in-the-string in French, and to the mutual cancelling out of these effects in English. The third participant exhibited a non-head constituent advantage in both languages, indicating that semantic modification of the head constituent by the non-head constituent plays a prominent role in her accessing procedures. For all three participants, phonological similarity influenced production, while grammatical category did not. Conclusions: Our results reveal that headedness and position interact in the processing of compounds. They also demonstrate that compound constituents are processed asymmetrically across and within languages, thus confirming that people with aphasia are sensitive to compound-internal structure. Moreover, they show that patients rely on varying structural information when accessing compounds.