title: Parallel functional category deficits in clauses and nominal phrases: The case of English agrammatism.
abstract: Individuals with agrammatic aphasia exhibit restricted patterns of impairment of functional morphemes, however, syntactic characterization of the impairment is controversial. Previous studies have focused on functional morphology in clauses only. This study extends the empirical domain by testing functional morphemes in English nominal phrases in aphasia and comparing patients' impairment to their impairment of functional morphemes in English clauses. In the linguistics literature, it is assumed that clauses and nominal phrases are structurally parallel but exhibit inflectional differences. The results of the present study indicated that aphasic speakers evinced similar impairment patterns in clauses and nominal phrases. These findings are consistent with the Distributed Morphology Hypothesis (DMH), suggesting that the source of functional morphology deficits among agrammatics relates to difficulty implementing rules that convert inflectional features into morphemes. Our findings, however, are inconsistent with the Tree Pruning Hypothesis (TPH), which suggests that patients have difficulty building complex hierarchical structures.
authors.affiliation: Department of Linguistics, Northwestern University, Evanston, IL, USA ; College of Foreign Languages, Beihang University, Beijing, China.
authors.forename: Honglei
authors.initials: H
authors.lastname: Wang
authors.affiliation: Department of Linguistics, Northwestern University, Evanston, IL, USA.
authors.forename: Masaya
authors.initials: M
authors.lastname: Yoshida
authors.affiliation: Department of Communication Sciences and Disorders, Northwestern University, Evanston, IL, USA ; Department of Neurology, Northwestern University, Chicago, IL, USA ; Cognitive Neurology and Alzheimer's Disease Center, Northwestern University, Chicago, IL, USA.
authors.forename: Cynthia K
authors.initials: CK
authors.lastname: Thompson
keywords: Agrammatic aphasia; Clause; Functional category; Nominal phrase