Two-year-olds with larger oral vocabularies enter kindergarten better prepared

The study was conducted by researchers at the Pennsylvania State University, the University of California, Irvine, and Columbia University, who analyzed nationally representative data for 8,650 children in the Early Childhood Longitudinal Study-Birth Cohort. The study appears in the journal Child Development.

Two-year-olds' vocabularies were measured via a parent survey, and their academic achievement in kindergarten was gauged via individually administered measures of reading and math. Kindergarten teachers independently rated the children's behavioral self-regulation and frequency of acting out or anxious behavior. Researchers took into account a wide range of background characteristics (such as sociodemographics) and experiences (such as parenting quality) to more fully isolate the role of vocabulary growth. They evaluated whether 2-year-olds with larger oral vocabularies achieved more academically and functioned at more optimal levels behaviorally when they later entered kindergarten.

Gaps in oral vocabulary were evident between specific groups of children as young as age 2, with children from higher-income families, females, and those experiencing higher-quality parenting having larger oral vocabularies than their peers. Children born with very low birthweight or from households where the mother had health problems had smaller oral vocabularies.

When the researchers examined the children three years later, they found that children who had a larger oral vocabulary at age 2 were better prepared academically and behaviorally for kindergarten, with greater reading and math achievement, better behavioral self-regulation, and fewer acting out or anxiety-related problem behaviors. This oral vocabulary advantage could not be explained by many other factors, including the children's own general cognitive and behavioral functioning and the families' socioeconomic resources.

"Our findings provide compelling evidence for oral vocabulary's theorized importance as a multifaceted contributor to children's early development," notes Paul Morgan, associate professor of education at the Pennsylvania State University, who led the study. "Our findings are also consistent with prior work suggesting that parents who are stressed, overburdened, less engaged, and who experience less social support may talk, read, or otherwise interact with their children less frequently, resulting in their children acquiring smaller oral vocabularies."

Adds George Farkas, professor of education at the University of California, Irvine, who coauthored the study: "These oral vocabulary gaps emerge as early as 2 years. Early interventions that effectively increase the size of children's oral vocabulary may help at-risk 2-year-olds subsequently enter kindergarten classrooms better prepared academically and behaviorally. Interventions may need to be targeted to 2-year-olds being raised in disadvantaged home environments."

Examples of such interventions include home visitation programs, through which nurses regularly visit disadvantaged first-time mothers during and after their pregnancies to help with parenting matters and link them with social services and other support systems. These could play an important role in the school readiness of disadvantaged children, the authors suggest.