Word knowledge acquisition in retarded children: a longitudinal study of acquisition of a complex linguistic structure.

The purpose of this 1-year longitudinal study was to investigate the acquisition of word knowledge by 18 retarded children. The words examined were relevant to the correct interpretation of sentences of the type "John is eager/easy to please." The interest was in how retarded children acquire the subcategorization features of these words. The study revealed that retarded children, like intellectually normal children, show great inconsistencies in their interpretations of specific words during an intermediate stage of performance on this linguistic structure; but the errors by retarded children, in contrast to those by intellectually normal children, were highly correlated with word frequency. The results are interpreted in representations. Interpretations based on gradual acquisition of word knowledge are contrasted with a reorganization theory, and a synthesis of the two views is given. Possible explanations for the finding that the retarded children nevertheless differed from intellectually normal children in the relation of their errors to word frequency are also given.