Five experiments examined whether overt repetition (i.e., saying a word aloud) during exposure is critical to the expressive learning of new words. When participants did not engage in overt repetition during exposure, they nevertheless exhibited clear expressive learning, both with and without an accompanying semantics, indicating that overt…

Comparison of language-impaired two- to three-year-olds (N=10) and normal one-year-olds (N=15) matched for expressive language revealed that the language-impaired subjects acquired a greater number of object concepts presented in a no-action condition than the normal children, although language-impaired subjects' extensions of the names to new…