Grammatical form and semantic context in verb learning.

Decades of research have documented that young word learners have more difficulty learning verbs than nouns. Nonetheless, recent evidence has uncovered conditions under which children as young as 24 months succeed. Here, we focus in on the kind of linguistic information that undergirds 24-month-olds' success. We introduced 24-month-olds to novel words (either nouns or verbs) as they watched dynamic scenes (e.g., a man waving a balloon); the novel words were presented in semantic contexts that were either rich (e.g., The man is pilking a balloon), or more sparse (e.g., He's pilking it). Toddlers successfully learned nouns in both the semantically rich and sparse contexts, but learned verbs only in the rich context. This documents that to learn the meaning of a novel verb, English-acquiring toddlers take advantage of the semantically rich information provided in lexicalized noun phrases. Implications for cross-linguistic theories of acquisition are discussed.