ABSTRACT
The five empirical articles in this special issue illustrate the value o f a com parative approach to the study of normal and abnormal language development. The infor mation presented here does not just add up; it multiplies, yielding insights that would not be available from any of the individual parts examined alone. All five articles focus on the first stages of language learning, from first signs o f word com prehension to the em ergence of grammar. They underscore the immense variation that can be observed in normal children, and the range o f ways that language can break down or go awry in the early stages. These results place im portant constraints on our understanding of the origins o f com m unication disor ders. At the same time, they provide substantial hope to families o f children who are not developing on a normal schedule, dem onstrating there may be several different paths to the achievement of language abilities within the normal range. The human language faculty is remarkably plastic, at least within the early stages. To be sure, there are some circumstances in which this plasticity appears to be quite limited. Here too, however, there are reasons to believe that our increased knowl edge of the origins of com munication disorders may lead to treatments that release children from these lim itations on plasticity and learning, placing them on the road to recovery.
