30 working-class and 33 upper-middle-class mothers were videotaped in dyadic interaction with their 18-29-month-old children in 4 settings--mealtime, dressing, book reading, and toy play. Samples of the mothers' adult-directed speech also were collected. There were significant social class differences in the mothers' child-directed speech and some parallel social class differences in the mothers' adult-directed speech. These findings suggested that some social class differences in child-directed speech may be instances of more general class differences in language use. There also were main effects of communicative setting on mothers' child-directed speech and interaction effects in which setting moderated the size of the class differences in maternal speech. These findings suggested that the amount of time mothers spend interacting with their children in different contexts may be at least as important an influence on children's linguistic experience as are average characteristics of their mothers' speech.

Variation in mothers' child-directed speech and in their children's rates of language development were examined as a function of child birth order and family socioeconomic status (SES). A total of 63 children between 18 and 29 months were recorded in dyadic interaction with their mothers on two separate occasions, 10 weeks apart. The children included first and later boms who came from high-SES and mid-SES backgrounds. Analyses of the children's speech at the second visit showed that the first-bom children were more advanced in lexical and grammatical development than the later-bom children, and that the later-bom children were more advanced in the development of conversational skill. High-SES children showed more advanced lexical development than mid-SES children. These differences are interpreted as the result of differences in language learning experience associated with birth order and SES, some of which were in evidence in the mothers' speech recorded at the first visit. With respect to theories of language acquisition, these findings suggest that language experience plays a nontrivial role in language development, and that the nature of that role is different for different components of language development. With respect to general developmental consequences of birth order and SES, the findings indicate that differences in early language experience may set the stage for later developmental differences, but that when long-term and pervasive differences are observed, as is the case for SES-related differences in achievement, it is likely that there are pervasive and continuing differences in experience.

30 working-class and 33 upper-middle-class mothers were videotaped in dyadic interaction with their 18-29-month-old children in 4 settings--mealtime, dressing, book reading, and toy play. Samples of the mothers' adult-directed speech also were collected. There were significant social class differences in the mothers' child-directed speech and some parallel social class differences in the mothers' adult-directed speech. These findings suggested that some social class differences in child-directed speech may be instances of more general class differences in language use. There also were main effects of communicative setting on mothers' child-directed speech and interaction effects in which setting moderated the size of the class differences in maternal speech. These findings suggested that the amount of time mothers spend interacting with their children in different contexts may be at least as important an influence on children's linguistic experience as are average characteristics of their mothers' speech.

This study investigated the extent to which the nature of verb input accounts for the order in which children acquire verbs. We assessed the nature of verb input using a combined sample of the speech of 57 mothers addressing their Stage I children. We assessed the order of verb acquisition using as our database a combined sample of those children's speech 10 weeks later and using as our measure of order of acquisition the frequency of verb occurrence. The first set of analyses established the validity of this measure of acquisition order by comparing it with order of acquisition data obtained from checklist and diary data. The second set of analyses revealed that three properties of the input were significant predictors of the order of acquisition of the 25 verbs that were the focus of this study. The predictive properties of input were the total frequency, final position frequency, and diversity of syntactic environments in which the verbs appeared. These findings suggest that the way verbs appear in input influences their ease of acquisition. More specifically, the effect of syntactic diversity in input provides support for the syntactic bootstrapping account of how children use structural information to learn the meaning of new verbs.

The relationship over time between properties of mothers' speech and the rate of their children's syntax growth was investigated. The data base consisted of transcripts of mother-child conversation collected at 2-month intervals for a period of 6 months for 22 two-year-old children and their mothers. The results suggested that both mothers' communicative goals in talking to their children and structural characteristics of mothers' speech can influence their children's language development. The findings are discussed in terms of how children make use of the speech they hear in constructing the grammar of their language.