In this article, the author explores the phenomenon of children's language choice and language use in a Korean-English two-way immersion (TWI) program. She does so by drawing on situations in which the children spoke of the principles guiding their choice of languages, and instances in which they voluntarily adopted Korean as the means of communication and made efforts to use Korean. Instances in which the children voluntarily chose to use Korean amongst themselves were few and far between, but this latter focus is an effort to understand the contextual features--mainly the linguistic and the social--of language choice, and to see under what conditions Korean was utilized by the children--why it was adopted, and how it was used. This focus is in line with the theoretical argument of this paper that power in language is contextual and its dynamics are defined by the context within which it operates. The research questions for this project are as follows: (1) What are the children's understandings of the two languages that guide their choice and use of the languages?; (2) What are the dynamics underlying the children choice of Korean and their subsequent uses of the language?; (3) What are the dimensions of interaction that matter?; and (4) what can be learned from this study about the nature of language learning that can be applied to other language learning situations? The author addresses the implications of this research for classroom practice and demonstrates the importance of putting children and their social relationships at the forefront of pedagogical decisions.