Applied Psycholinguistics


Size matters: Early vocabulary as a predictor of language and literacy competence


a1 Wilfrid Laurier University


This paper investigated the predictive ability of expressive vocabulary size and lexical composition at age 2 on later language and literacy skills from ages 3 through 11. Multivariate analysis of covariance was performed to compare 16 language and literacy outcomes between children with large expressive vocabulary size at 24 months (N = 1,073) and those with smaller expressive vocabulary size. Comparisons between large and small verb size groups as a measure of lexical composition were also conducted. Our findings indicate that, after controlling for gender, birth order, ethnicity and socioeconomic status, total vocabulary size at age 2 can significantly predict subsequent language and literacy achievement up to fifth grade. Moreover, vocabulary size is a better predictor of later language ability than lexical composition.

(Received October 25 2008)

(Accepted September 19 2009)


c1 ADDRESS FOR CORRESPONDENCE Joanne Lee, Department of Psychology, Wilfrid Laurier University, 75 University Avenue West, Waterloo, ON N2L 3C5, Canada. E-mail: