Investigates the acquisition of elements that instantiate the grammatical category of "inflection"--copula "be," auxiliary "be" and 3sg present agreement--in longitudinal transcripts from five children, aged from 1 year and 6 months to 3 years and 5 months in the corpora examined. Aimed to determine whether inflection emerges as a unitary category, as predicted by recent generative accounts, or whether it develops in a more piecemeal fashion, consistent with constructivist accounts. (Author/VWL)