Teacher study groups (TSGs) contribute to professional development when participants explore, articulate, and extend their personal professional knowledge in a supportive setting. In this study of cultural variables in the English-as-a-Second-Language (ESL) classroom, tensions among aspects of professional accountability and responsibility surfaced repeatedly, reflecting varying degrees of satisfaction in participants' views of their success as teachers. It was thus possible to propose a theoretical model of personal practical knowledge indicating these tensions and the resulting zones of relative comfort and discomfort with respect to accountability and responsibility. This theoretical model has important implications for the content and ethos of language teacher education programs, particularly regarding the need for preparation in areas beyond the necessary foundation in linguistic and pedagogical theory. (Author/SM)