The inferential use of linguistic and extralinguistic information in structuring conversations was studied in 90 three- and five-year-old children. Pictures portraying an actor-action-object relation, e.g., a child picking a flower, were used to guide conversational sequences. Both active pictures (which emphasized an action relating actor and object via postural cues) and static pictures (which did not) were used. Linguistic topics were implied by prefacing each picture with comments topicalizing actor, action, or object. Neutral control groups were run in which no topic was implied and, in an explicit control group, the actor's action on the object was directly topicalized for three-year-olds. Neither actor, action, nor object productions of three-year-olds varied significantly with topic; explicitly defining a topic increased the incidence of action and object responses and induced pronominalization or ellipsis of actor. Five-year-olds ellipsed or pronominalized actors for implied object and gave fewer action and object productions when actor was implied. Indefinite articles were used more than definite by both groups. Five-year-olds are clearly sensitive to implicit linguistic topics, whereas three-year-olds seem to require explicit topic definition for contingent replies. The increase in object utterances to active pictures is taken to support the notion that extralinguistic information may guide early linguistic productions and conversations. (Author)