TURNABOUTS, which both respond to and require a response from the other (either verbal or nonverbal), were produced more than twice as often by mothers as by their children at 2; 2 and 2; 6, in videotaped dialogues during semi-structured play. The 27 mothers showed stable individual differences in this aspect of their turn-taking, across situations and across time. Children tended to take a reciprocal role rather than an imitative one within the immediate situation: if a mother produced many mands, her child produced few. At 2; 10 the children were tested for language comprehension, puzzle-solving and conversational engagement with an investigator. Mothers' mands at the earlier ages appeared to have a negative effect upon these measures, even when social class differences were controlled; but causal interpretations were complicated by the fact that language production measures also predicted the 2; 10 cognitive measures.