Across a diverse range of languages, children proceed through similar stages in their production of causal language: their initial verbs lack internal causal structure, followed by a period during which they produce causative overgeneralizations, indicating knowledge of a productive causative rule. We asked in this study whether a child not…

Using multi-level growth modeling, we examined the effect of several measures of maternal input on growth in children's word types from 15-54 months. Mothers and children engaged in a picture description task (N = 77) at 15, 24, 33, and 54 months; the frequency of children's observed word types at each wave was coded and additional independent…