Using an events-history approach with 40 child-mother dyads, researchers examined prediction from three indexes of children's language, starting at 0;9, and mothers' verbal responsiveness at 0;9 and 1;1, investigating development of language milestones in year 2. Together, children's initial propensities to speak and mothers' responsiveness at the start of year 2 largely influenced children's achievement of language milestones. (SM)