Study of language development has been the focus of attention of a number of professions concerned with early childhood. Because language development plays a crucial role in social and cognitive development it has attracted the attention of educators and clinicians. Social and cognitive development, in turn, play a role in language development. In addition, the effect of biological state and maturation on language development has been a focus of attention. Researchers have studied premature as compared to full-term infants in hopes of determining the effects of biological state on development. Many studies have explored speech and language mastery in both fiill-term and premature infants as a way of examining whether or not there are early and late differences that can be found in this development due to prematurity per se or to the complicating medical or social factors that accompany prematurity. As stated, language development has been a focus of attention because of the important role it plays in social and academic development, although other aspects of development can be affected by prematurity and accompanying factors. (For further information on recent studies of the effect of prematurity on a number of aspects of development, outside of language development, during the early years of life, readers can look at Rosenblith, 1992.)
The questions of the comparative effect o f social, cognitive, and biological factors and their interaction on language development has been examined in many studies. The answer to these questions are of theoretical and applied interest. The theoretical interest is that of explanation of this important development. The applied interest is to determine what may be important early deviations from normal patterns so that intervention may be planned. The study reported on in this volume was undertaken also to examine these
theoretical and applied questions. The primary study took place from 1982 to 1985. Although a great deal has been learned from many studies before and after the study, the questions have still not been thoroughly answered. The results of this study, we believe, contribute to the answers.