Differences in vocabulary that children bring with them to school can be traced back to the gestures they produced at the age of 1;2, which, in turn, can be traced back to the gestures their parents produced at the same age (Rowe & Goldin-Meadow, 2009a). We ask here whether child gesture can be experimentally increased and, if so, whether the increases lead to increases in spoken vocabulary. Fifteen children aged 1;5 participated in an 8-week at-home intervention study (6 weekly training sessions plus follow-up 2 weeks later) in which all were exposed to object words, but only some were told to point at the named objects. Before each training session and at follow-up, children interacted naturally with caregivers to establish a baseline against which changes in communication were measured. Children who were told to gesture increased the number of gesture meanings they conveyed, not only during training but also during interactions with caregivers. These experimentally induced increases in gesture led to larger spoken repertoires at follow-up.