The role of mothers' speech for children's education beyond the early years

We tested the extent to which mothers' speech contributes to the transmission of family background inequality in education. In 894 families (93.1% White), representative of the full range of Britain's socioeconomic conditions, we quantified mothers' vocabulary sophistication, lexical diversity, and grammatical complexity from 10-min-long audio-recorded interviews. Mothers' vocabulary sophistication significantly predicted children's (49% males) cognition, literacy, and educational achievement from ages 5 to 12 years, accounting for 2%–5% of the variance. After adjusting for mothers' education and household income, these effects reduced to 1% and 2% or became nonsignificant. Our findings suggest vocabulary sophistication contributes only modestly to the transmission of family background inequality in education.