The processes involved in defining oral proficiency in second languages have to date not involved detailed analysis of the discourse characteristic of oral proficiency interviews. This study considers the phenomenon of variation in questions posed by interviewers at key junctures in the interview process. Based on variable rule analyses of 16 full-length oral proficiency interviews, it is argued that perceptions of oral proficiency are reflected in the extent of accommodation in interviewer questioning, and that the extent of accom modation may provide a powerful factor in determining oral proficiency as well as a criterion for interviewer training.