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Properties of adult and adolescent mothers' speech, children's verbal performance and cognitive development in different socioeconomic groups: a longitudinal study∗

The research analysed longitudinally the properties of maternal utterances and their relation with child's language and cognitive development. The sample consisted of 125 mother-child dyads divided in three groups: 32 adolescent mothers, 54 adult mothers of low socioeconomic status (LSES), and 39 adult mothers of middle socioeconomic status (MSES). The form and function of each mother's utterances to her child at 18, 30 and 36 months of age were evaluated during a free-play session in the laboratory. Results showed differences between the three groups in the properties of maternal utterances. Adolescent and adult LSES mothers used more utterances that controlled or directed what the child was doing, and fewer utterances that informed or questioned the child. During their second and third year of life, children from the MSES group obtained higher scores than children of adolescent and adult LSES mothers on measures of language and cognitive development. Multiple regression analysis revealed that the forms and functions of maternal utterances were important predictors of child development. Most importantly, the forms and functions of maternal utterances from 18 to 36 months explained 45% of the variance in the children's score on the Stanford-Binet.