Disorders of Morphology in Aphasia

In this chapter we will review some stable findings on the impairment at the morphological level. Areas of difficulties for people with aphasia have been reported in the process of composition, where compound words are stored as the sum of their individual parts and the individual word that determines the word class of the compound is less affected than the other(s); in affixation, with a particular impairment in suffixation, the process that changes grammatical class in a word and – in some languages – contains syntactic information, over prefixation, which only changes word meaning; related to word classes, a dissociation between noun and verb production has been detected. Perhaps the most impaired part of morphology is arguably that on inflectional morphology on finite verbs, where a dissociation between verb tense and subject–verb agreement has been reported cross-linguistically and discussed extensively in the literature on aphasia.