This meta-analytic review explored the characteristics and effectiveness of combined language (e.g., vocabulary) and code (e.g., phonological awareness) interventions, including synergistic intervention effects for at-risk preschoolers. Data from 29 randomized controlled trials, published before March 2023, reporting on 43 interventions, including…

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…

Interventions that train parents to share picture books with children are seen as a strategy for supporting child language development. We conducted meta-analyses using robust variance estimation modeling on results from 19 RCTs (N[subscript total] = 2,594; M[subscript child age] = 1-6 years). Overall, book-sharing interventions had a small sized…

Presents evidence for four major design features of serial organization of speech arising from comparison of babbling and early speech with patterns in ten languages. Maintains that no explanation for the design features is available from Universal Grammar; except for intercyclical consonant repetition development, perceptual-motor learning seems…