Four children (aged 3;9 to 5;5) were recorded talking to different listeners (adult, peer, baby, and baby doll) and role-playing a ‘baby just learning how to talk’. As a measure of the children's responsiveness to situational cues, each sample was analysed for formal and functional characteristics. The children's speech was different on many of the measures when talking to a baby or doll as compared with the speech to a peer or adult. Speech to a baby doll was similar to that addressed to a real baby, indicating that feedback is not necessary for speech modifications to occur. In the role-playing situation, children changed and simplified their speech when talking as a baby.