How two aphasic speakers construct subject-Verb agreement

The processes by which two aphasics constructed subject-verb agreement in speech were examined using two experiments in which subjects had to complete a sentence preamble (Bock and Miller, Cognitive Psychology 23, 35-43, 1991). Both patients had good comprehension and performed at similar level, though significantly worse than normal, in the first experiment. In the second experiment, one aphasic, classified as agrammatic, showed normal sensitivity to semantic and morphological variables in the preamble. The second patient, classified as conduction aphasic, showed sensitivity to neither variable. The theoretical implications of a selective inability to make use of semantic and morphological information are discussed.