School socializes children into institutional and academic practices. Because socialization occurs over time, it cannot be analyzed simply by describing typical speech events that occur in school. In addition, we must analyze trajectories of events across which schoolchildren become different kinds of people. This paper analyzes the social identification that occurred in one ninth grade U.S. high school English and history classroom over an academic year, tracing events across which one student developed a distinctive social identity. The analysis attends to more widely circulating categories and practices, but also describes how these were contextualized and sometimes transformed both in the local classroom ecology and in particular events. The paper first describes a robust local model of gender identity, through which teachers and students identified the girls as academically promising and the boys as academically unpromising. It illustrates this model by showing how the prototypical boy was identified across the year. Then the paper describes the transformation of a normal promising girl into an atypical, unpromising girl over several months in the middle of the academic year. The analyses follow this girl through many speech events across these months, tracing how her classroom identity changed. These analyses show how an account of socialization must move beyond typical speech events to trajectories of events across timescales.