Prelinguistic predictors of language growth in children with developmental disabilities.

This study followed 18 children with developmental disabilities, whose chronological ages were between 3 years and 6 years at the start of the study, over a 2-year period. At initial observation, children communicated primarily through prelinguistic gestures, vocalizations, and single-word utterances. Children's language skills were measured every 6 months with the Sequenced Inventory of Communication Development-Revised (D. E. Hedrick, E. M. Prather, and A. R. Tobin, 1984). Prelinguistic communication rate and parental responsiveness were also measured at each observation. Development of language over time differed between participants in accordance with their entry-level communication. Hierarchical linear modeling indicated that children's level of gestural attainment, rate of communication, and parent response contingency were significant predictors of language outcome.