Prior research points to gender differences in some early language skills, but is inconclusive about the mechanisms at play, providing evidence that both infants' early input and productions may differ by gender. This study examined the linguistic input and early productions of 44 American English-learning infants (93% White) in a longitudinal…

Previous studies have found correlations between parent input and child language outcomes, providing prima facie evidence for a causal relation. However, this could also reflect the effects of shared genes. The present study removed this genetic confound by measuring English vocabulary growth in 29 preschool-aged children (21 girls) aged…

This meta-analysis examined associations between the quantity and quality of parental linguistic input and children's language. Pooled effect size for quality (i.e., vocabulary diversity and syntactic complexity; k = 35; N = 1,958; r = .33) was more robust than for quantity (i.e., number of words/tokens/utterances; k = 33; N = 1,411; r = .20) of…

This study employs the Specificity Principle to examine the relative impacts of external (input quantity at home and at school, number of books and reading frequency at home, teachers' degree and experience, language usage, socioeconomic status) and internal factors (children's working memory, nonverbal intelligence, learning-related…

The mothers of 29 Spanish English bilingual 25-month-olds kept diary records of their children's dual language exposure and provided information on their children's English and Spanish language development using the MacArthur-Bates inventories. Relative amount of exposure predicted language outcomes in English and Spanish. In addition, the number…