Are Communicative Gestures the Substrate of Language?

The relationship between communicative gestures and language acquisition was investigated in 30 infants who were visited at home four times between 9 months and 3 years. At 9 and 15 months, they were videotaped in free play with their mothers, and their communicative gestures were coded from these interactions. At three years, measures of spontaneous speech, receptive vocabulary, and communicative competence were obtained. So-called primitive gestures, Protest/Rejection and some forms of Request, were found to decline in the second year and to be negatively related to measures of language production at 3 years. Object Exchange and Comment gestures, in contrast, increased in the second year and were positively related to language measures, the first to early vocabulary size and the second to 3-year-old receptive vocabulary. Gesturing as a whole did not decline with the onset of language, and the co-ordination of gestures with vocalizations increased. These findings support both a precursor model and an interdependent model of the relationship of gestures to language.