Dwyer, A. 1, 2 , Jones, C. 1, 2 , Kitamura, C. 1 , Davis, C. . 1 & Ching, T. 3
1 MARCS Institute for Brain, Behaviour and Development, Western Sydney University
2 ARC Centre of Excellence for the Dynamics of Language
3 National Acoustic Laboratories, Macquarie University
Early differences in children's vocabulary related to socioeconomic status (SES) have been attributed, in part, to the language environment at home. In this longitudinal study we examined quantitative aspects of infants' early linguistic experience at home, to assess SES differences and their potential association with later expressive vocabulary skills.
Fifty families participated from working- and middle-class Australian English-speaking backgrounds, representing two levels of maternal education (<bachelor degree, >bachelor degree).
At 6 - 9 and 12 - 15 months, adult word, conversational turn and child vocalisation counts were extracted from 12-hour recordings of infants' interactions with their family. At 12 - 15 and 19 months parents reported on children's expressive vocabulary using the Australian English Communicative Development Inventory (OZI).
Higher maternal education was significantly associated with higher adult word and conversational turn counts (p < .05), but not child vocalisation counts (p > .05). In turn, conversational turn counts accounted for up to 27% of variance in infants' later vocabulary scores.
Briefly, results indicate a largely indirect relationship between maternal education and expressive vocabulary at 12-15 and 19 months that operates via earlier conversational interaction from 6-9 months and may be moderated by sex differences. Detailed findings will be presented.