Introduction

One of the goals of linguistic research is to understand how language functions in the brain. Although it is rarely possible to observe the brain directly, fortunately there are clues as to the nature of the neurological mechanisms underlying language. A particularly useful source of such clues comes from the patterns of linguistic deficits observed in brain-damaged aphasic patients. Among the many forms of aphasia that can occur, one of the most informative from the point of view of linguistic research is ‘agrammatism’ in non-fluent Broca's aphasia, which is generally taken to involve deficits in morphological and syntactic levels of processing (cf. Caplan, 1991).

Findings from research on agrammatism are of importance in that they can provide evidence for established linguistic theories, in addition to providing valuable clues about both the nature of the syntactic disorder itself and the neurological mechanisms underlying language. This research can also advance therapies to help rehabilitate aphasic patients. Because of its importance, researchers have extensively studied agrammatism in Indo-European languages such as English and German since the late 1970s. The most widely investigated hypotheses in this research attribute agrammatism either to the loss of syntactic knowledge or to damage to cognitive resources, which in turn compromises the ability to process intact knowledge.

The properties of individual languages may modify the manifestations of the same aphasic syndromes.