The child encounters culture, to a great extent, through speech. The content of speech conveys the norms, the values, the accumulated knowledge and folkways of the society. However, the form of speech - that is, structured language – bears an uncertain relation to culture. Linguists, anthropologists, psychologists, and philosophers have taken every possible position on the role played by linguistic form in the thought and behavior of individuals and social groups. In my own comparative research on child language development I have sought to avoid these uncertain issues by attending to the acquisition of linguistic form itself, characterizing my approach as cross-linguistic, but not as cross-cultural. This approach is based on the empirical finding – from our early cross-cultural research (Slobin, 1970, 1973) – that patterns of grammatical development are strikingly similar in widely differing cultural settings; and on the psychological conviction that the course of language development is determined by biological and cognitive factors that are common to our species. Thus I have made use of linguistic diversity as a kind of “natural experiment” in which the world presents children with different tasks to solve.