ABSTRACT
This paper argues that a clear distinction should be made between the representation of linguistic knowledge and the use that is made of such a knowledge representation in processes of language comprehension and production. Observations from agrammatic aphasia support such a distinction: Patients still have the grammatical knowledge of their native language available, but cannot make use of it quickly enough in on-line processes of language production and comprehension. Instead, patients adapt to these limitations by using syntactic structures that are less complex, for instance, by omitting some functional projections; these simplified structures can be handled by patients, because they impose less burden on working memory. In the second part of the paper, it is shown that choices of the impaired system, more specifically these adaptive simplifications of syntactic structure, are directed by the grammatical representation of the language. They interact with probabilistic information in the form of markedness.
