On certain grammatical prerequisites for agrammatic behaviour in comprehension

Abstract The present article examines the logical consistency of the interpretation of agrammatic deficits in comprehension in terms of the loss of syntactic processes and/or closed-class morphology. Drawing on a variety of neurolinguistic evidence and considering the structure of language comprehension tasks, we develop the argument that this account is logically untenable. We show that agrammatic behaviour in comprehension presupposes, in fact, the ability to run the morpho-syntactic disambiguation (MSD) of words in sentences. MSD, which consists in determining the lexical identity and syntactic category of words, is defined as the preliminary operation in language comprehension. This operation can only be done on the basis of grammatical rules and has to take into account all the words of a sentence. The running of MSD is necessary because the lexical identity and syntactic category of words in utterances is a priori indeterminate. Several implications of the present position are discussed and a new approach to the study of agrammatism is outlined. In particular, we explore the possibility that MSD in French involves gender determination by the article and, accordingly, that French speaking agrammatics are sensitive to this information. This prediction is borne out by a study, in four experiments, of the linguistic behaviour in comprehension of an agrammatic patient.