Morphological deficits in agrammatic aphasia : a comparative linguistic study

In this thesis, a comparative linguistic investigation of morphological deficits in two English-speaking and two Greek-speaking agrammatic aphasic patients is presented. Adopting the Strong Lexicalist Hypothesis, the study focuses on the subjects' ability to repeat, comprehend and produce nominal and verbal inflections. The hypotheses investigated concern the effects of language-specific features in agrammatic performance and the role of morphological principles in the two languages. Finally the implications of the data for linguistic theory are investigated.The data show that language-specific features are crucial in determining aphasic performance. Principles of well-formedness of lexical items appear to remain unaffected. Morphological deficits are found to manifest themselves at different levels: the lexical and the postlexical. A Storage Hypothesis which reflects the word structure of complex lexical items in the brain is proposed. Finally, it is proposed that only through a Strong Lexicalist framework can one achieve uniform interpretations of morphological deficits in aphasia