This project investigates how American students interning in Japan develop language skills, identities, and professional participation through immersive workplace experiences, drawing on ethnographic fieldwork conducted across multiple regions and industries. Rather than viewing language learning solely as measurable gains, Hae Ree Jun’s study reconceptualizes it as a dynamic, reflexive process shaped by learners’ ongoing negotiation of linguistic, cultural, and professional identities within the target-language and global communities. Using qualitative methods, including interviews, workplace interaction recordings, observational field notes, and students’ coursework, the research examines how interns navigate their roles as students, professionals, and foreigners, and how they deliberately mobilize linguistic resources to participate in Japanese workplaces. In particular, it explores how participants construct their linguistic and professional selves in dialogue with broader sociocultural contexts, including spatial arrangements, interactional expectations, and linguacultural and institutional norms. By foregrounding identity formation and participation, the project contributes to applied linguistics and the humanities by offering a holistic understanding of language learning as a transformative, human-centered process embedded in real-world social interaction.