The emergence of the ability to maintain and develop a topic of conversation is examined. The production of a competently structured topic involves utterances that are both propositionally contingent on previous utterances and related to the global concern of the topic. Children under 2 years of age can only product utterances that are contingently relevant. Videotaped mother-child interactions involving five English children under the age of 2 were analyzed. It was demonstrated that routinized interaction provides lessons in culturally expected behavior and a frame within which children can exhibit an increasing amount of planned conversational contributions, until they reach the point where they no longer need the prompting of routines. The development of the ability to sustain a topic is defined in terms of three stages in which the child's discourse is progressively less controlled by adult forces and more by the child's own discourse capabilities. (RW)