A discussion of teacher education focuses on how teachers' conceptions of classroom practice are influenced by their participation in a graduate inservice teacher education program. It is based on a longitudinal study following four high school foreign language teachers through an inservice program. Participants were observed in five phases: pre-matriculation; two consecutive summers of course work; the intervening school year, including a practicum; and the school year after the second summer's study. Data were gathered in interviews, observation, and documents written by the teachers during the program. Both intensive individual case studies and cross-case analysis were included. Results suggest that as the teachers learn to articulate their tacitly-held ideas about teaching through the shared discourse of the in-service program, they gained greater control in shaping classroom practice. Three concepts are developed in the analysis that focus on local and professional language and articulation and concepts of practice. The discussion concludes with questions on the nature of teachers' conceptions of practice and on the durability of the changes brought about by the articulation of those conceptions in professional discourse. (32 references) (MSE)