Symbol vocabulary and the focus of conversations: augmenting language development for youth with mental retardation.

Communication devices designed to augment the language development of individuals with severe cognitive disabilities and little or no functional speech typically contain primarily nouns because they seem easiest to acquire and evaluate. In this study, the effect of a more diverse vocabulary was assessed. Systematic observations of the use of computerized speech-output devices by 12 youth with moderate or severe mental retardation and severe spoken language disability and by their partners were made over a 2-year period. Social-regulative symbols (e.g., "please," "I'm finished") were used as soon as they were introduced, and their availability expanded the focus of conversations both at home and at school. Implications for conceptualizing variation in early language use and for the design of language intervention programs are discussed.