Prelinguistic pragmatic functions as predictors of later expressive vocabulary

This study tested the relationship between prelinguistic pragmatic function s and later expressive vocabulary of children with mild to moderate develop mental delays. Fifty eight toddlers with Bayley Mental Development Indices from 35-85 participated All children had fewer than 3 words in their expres sive vocabularies and showed at least one instance of intentional prelingui stic communication prior to testing. At the beginning of the study, childre n's prelinguistic behavior regulation, social interaction, and joint attent ion were measured. One year later, children's expressive vocabulary was mea sured. Results indicated that rate of joint attention and rate of communica tion were statistically significant predictors of later expressive vocabula ry. Rate of behavior regulation was not a predictor. There were too few ins tances of social interaction to test its predictive validity.