How mothers’ speech influences children’s cognitive abilities, literacy skills, and educational achievement

Mothers are the target of many interventions that seek to improve children’s life outcomes. Mother’s speech has been identified as a key contributor to the language gap observed between under-resourced children underperforming academically in comparison to their well-resourced peers. Prior studies mainly focus on mothers’ child-directed speech, thereby perpetuating a deficit model that designates language patterns typical of high socioeconomic status (SES) families as the norm. Several small-scale studies have reported sizeable effects of mothers' child- directed speech on children's language during the preschool years, but no longitudinal studies have tested the long-term associations of mothers' speech with children’s development. Furthermore, previous studies of the link between maternal language input and children’s development did not address the issue of genetic confounding. Overcoming these earlier limitations, we capitalise here on naturalistic speech recordings of 894 mothers with twin children born in 1994 to 1996 in England and Wales. Our findings indicate that maternal vocabulary sophistication, rather than lexical diversity or grammar, correlates with children’s cognitive abilities at age 5 and literacy at age 7 and 10, but not with school performance at age 7-12. However, these associations diminish after accounting for family background factors. In a next step, we will expand our models to control for genetic confounding. Overall, mother’s speech modestly influences children's cognitive abilities, literacy skills, and educational achievement.