Guided by Giddens' structuration theory, this study highlights structures that both enable and constrain nonnative English-speaking teachers and students in American college classrooms. Before international teaching assistants (ITAs) step into their American classrooms, several semishaped class structures are already in place: students (mostly American) possess most mainstream American values and practices; students may avoid getting to know their ITA because they may feel that they will lose "power" to an individual not part of the primary (American) culture; students may possess negative stereotypes of ITAs because of unpleasant prior experiences with ITAs who struggled with the English language; and, more generally, students may possess intuitive doubts about an ITA's ability to clearly communicate the course content. In essence, students' initial perceptions of ITA clarity, credibility, and language inadequacy coexist as constraining social structures that face ITAs in American instructional settings. Turning these structures into enabling mechanisms that smoothly facilitate the teaching and learning process poses a vital issue for ITAs. This study examined the effects of ITA self-disclosure of English language inadequacy on teacher clarity and credibility. Results indicate that an ITA's dialogic attempt to resolve language inadequacy has negative effects on student perceptions of classroom clarity. However, the findings point toward important benefits for enhanced teacher credibility for ITAs who use a dialogic approach to resolve language inadequacy. Theoretical and pedagogical implications and areas for future research are discussed. (Contains 2 notes and 3 tables.)