In this paper, I examine the way in which EFL speaking students use two languages, Korean and English, in the role plays during class that is English-mediated. This research is part of the larger research project on the policy of English as an official language and language use in English-only campus. The data were gathered by participant observation of language use in classroom and interview with students to discover their understandings of the policy and their responses. In this paper, utilizing the notion of ‘Third Space’ in literature and cultural studies, I examined speech events where English-Korean codeswitching occurrs to create a new space with new meanings. This paper suggests that participants’ language use is neither conforming nor resisting the norms informed by the policy, but reflects their creative ways of interpreting the norms which lead to the formation of Third Space.