Recent studies on language learning and teaching consider the relevance of psychological and social factors, relationships of individuals leading and idealizing learner-centered approaches, and reconstruction of world and social view, for examples, poststructuralist, sociocultural, and language socialization approaches on SLA (McKay & Wong, 1996, Norton, 2000, Pavlenko. 2000, 2001, 2002; Miller, 2000; Wenger, 1998 and etc.). This paper is a research to problematize what the researcher``s role in any research and its subjectivity. Throughout this research, my own identity has been shifted by destructuring myself as a researcher who shares same nationality with the participants. It was both of the participants and my self who experience sites of struggle during two-and-a half weeks of the class observation. The teacher also has changed her thought about her students. Identities were, therefore, renegotiated by the situation and interaction. Through out this study we can find how identities were co-constructed in the ESL classroom via interactions with others and via language itself.