In this paper we offer a longitudinal Conversation Analysis of talk lasting 18 months between a father and son, which reveals changes in the child's level of Interactional Competence (IC). We propose an index of developing IC based upon Sacks' distinction between "invited"and "volunteered"stories. While stories have a "socialization function"we suggest stories may be tracked in terms of IC also. What has been called "today narrative"routines ("What did you do at school today", etc.), initiated by the father, predominate in a series of conversations. The analysis reveals how the child is encouraged to take extended turns through the father's questions and comments, which are developed into a storytelling sequence. We observe that the child's responses to the initial inquiries become more elaborate over time. Furthermore, there is a gradual resistance to the invited story format because it inhibits how the child organizes his stories. Volunteered stories obtain a more personal 'voice'. The paper showcases the nexus between socialization and interactional competence.