Listen to Your Mother

Young children face a remarkable challenge in learning to use the language of their culture. Toddlers vary widely, however, in the rate at which they learn new words.¹ A team of Harvard Graduate School of Education researchers set out to ask whether and how children's language environment can impact vocabulary development. In their study of mother-child pairs from low-income families, they found that mothers who used many different words (not just many words) had toddlers with faster growth in vocabulary use.

During the toddler and preschool years, most children learn to use hundreds of words, combining them into sentences and engaging in conversation with others. From previous research, we know that variation in vocabulary growth relates to child characteristics like gender, and also to parental factors. For example, during the early stages, girls and firstborn children on average learn vocabulary somewhat more quickly than their peers.² On the environmental side, parents who talk more to their children have children whose vocabularies grow faster.³

Much prior research has focused on children from middle- to upper-class families, who in general tend to outpace those from low-income families in the rate at which their vocabulary size expands. Less is known about variation in vocabulary growth among children from low-income families, or what factors contribute to that variation. The work by HGSE researchers suggests that, for these low-income families, what matters most is the diversity of words that mothers use, not just the sheer number of words used.

To examine the relationship between language use by low-income mothers and their children, HGSE professors Barbara Alexander Pan, Judith Singer, and Catherine Snow, and former graduate student Meredith Rowe, Ed.M.'99, Ed.D.'03, studied a population of 108 families from a rural New England town. Most of these low-income families were white and spoke English as their primary language. To capture language and gesture use in a naturalistic setting, the researchers videotaped mothers and children in their homes, as they read a book together and played with age-appropriate toys at 14, 24, and 36 months of age. The data were analyzed to look at growth in children's vocabulary use over time.

What did they find? Like children from more affluent homes, these children varied widely in how quickly their vocabulary use grew during the infant and toddler years. Some children showed steady increase in vocabulary growth from 14 through 36 months of age, while others' vocabulary grew more slowly at first, and then faster later on. Mothers who used many different words (not just many words) had children with faster growth in vocabulary use. This relationship was particularly strong around the time of the children's second birthday.

Also, mothers who pointed a lot during the play sessions, as well as those with better developed language and literacy skills of their own, had children whose vocabulary use grew faster as they got older. Finally, higher levels of maternal depression were associated with slower growth of vocabulary use during play.

We know that vocabulary size is correlated with reading achievement during the primary school grades.⁴ So toddlers' success in acquiring vocabulary may have important consequences for their subsequent success in school. By age 3, many children from disadvantaged homes have begun to fall behind their more advantaged peers in vocabulary. However, as Pan's study demonstrates, not all children are alike, and there is a good deal of variation in word use among children from low-income families.

This study identified quality of mothers' talk — the diversity of the vocabulary they use — as a key predictor of disadvantaged children's growth in vocabulary use. The researchers conclude that while this study fills a gap in our knowledge of language growth in low-income populations, we need additional research, with samples more varied in ethnicity, race, and first language, to inform intervention efforts aimed at preparing children for success in school.

¹Huttenlocher, J., Haight, W., Bryk, A., Seltzer, M., & Lyons, T. (1991). Early vocabulary growth: Relation to language input and gender. Developmental Psychology, 27, 236-48.

²Bauer, D.J., Goldfield, B.A., & Reznick, J.S. (2002). Alternative approaches to analyzing individual differences in the rate of early vocabulary development. Applied Psycholinguistics, 23, 313-335.

³Hoff-Ginsberg, E. (1998). The relation of birth order and socioeconomic status to children's language experience and language development. Applied Psycholinguistics, 19, 603-29.

⁴Snow, C. E., Burns, S. M., & Griffin, P. (Eds.). (1998). Preventing reading difficulties in young children. Washington, DC: National Academy Press. 

This article is based on Pan, B.A., Rowe, M.L., Singer, J.D., & Snow, C.E. (2005). Maternal correlates of growth in toddler vocabulary production in low-income families. Child Development, 76, 763-782.