Further neurolinguistic evidence for morphological fractionation within the lexical system

Abstract In the cognitive neurolinguistic literature, several aphasic patients have been described who showed modality-specific difficulties in tasks requiring the processing of polymorphemic words and neologisms. In order to explain the observed error patterns in terms of a model of the lexicon, one has to argue in favour of specialized morphological components for the processing of polymorphemic stimuli, an assumption that is also proposed in some models of generative morphology as well as in the psycholinguistic literature. In experimental cognitive neurolinguistics it has been discussed how further developments within the logogen paradigm can explain functional disorders in processing mono- and polymorphemic words in a unified theory. The following article presents the results of four single case studies with patients clinically classified as agrammatics who showed dissociations of theoretically distinguishable word formation processes. It is discussed which special form of the morpholexical system has to be postulated to fit the experimental findings.