Does agrammatic speech constitute a regression to child language? A three-way comparison between agrammatic, child, and normal ellipsis.

When children are in the process of learning their mother tongue, they show frequent use of nonfinite clauses, even though they produce finite clauses at the same time, thereby demonstrating the availability of the functional domain associated with finiteness. In this study the hypothesis was tested that this behavior results from an overuse of the normal elliptical repertoire that has also been observed in agrammatic aphasia. The purpose of this overuse is prevention of computational overload. In support of the hypothesis it was found that children behaved very similar to aphasics and normal adults with respect to the following parameters: (a) distribution of types of ellipsis, (b) elaboration of ellipses, (c) word order, (d) subject omission, (e) frequency of weak subject pronouns, and (f) verb type (eventivity). The results also support the Jackson/Jakobson regression hypothesis, at least at the grammatical level.