Despite its recognized importance for cultural transmission, little is known about the role imitation plays in language learning. Three experiments examine how rates of imitation vary as a function of qualitative differences in the way language is used in a small indigenous community in Oaxaca, Mexico and three Western comparison groups. Data from one hundred thirty-eight 3- to 10-year-olds suggests that children selectively imitate when they understand the function of a given linguistic element because their culture makes frequent use of that function. When function is opaque, however, children imitate faithfully. This has implications for how children manage the imitation--innovation trade-off, and offers insight into why children imitate in language learning across development.