Young Children's Understanding of Present and Past Tense

Three age groups were tested for their understanding of present and past tense in the auxiliaries will and did, copula be, and progressive be. Children saw scenarios or pictures and responded to an experimenter's "show-me" requests based on the tensenon-past or past-of the verb in the request. For two groups (sixty-four 2-and sixty-four 3-year-olds), some children also heard temporal adverbs. The 2-year-olds successfully distinguished auxiliaries will/did and copula is/was, performing marginally on the progressive; adverbs produced no additional benefit. The 3-year-olds successfully distinguished all contrasts and showed more benefit of adverbs. The nine 4-year-olds performed at ceiling on all contrasts. Theresults suggest that knowledge of tense is neither localized to special lexical elements nor semantically based. From the beginning of combinatorial speech, children's grammars include a syntactic tense marker that is independent from aspect and include the syntactic category verb.