Situated in an English as a foreign language (EFL) context, this study navigates the intersection of language learner identity and foreign language engagement. Specifically, drawing on the concept of voice (Canagarajah, 2013; Johnstone, 1996; Kramsch, 2003), Bakhtin's (1981) theory of language, and the notion of investment (Darvin & Norton, 2015; Norton Peirce, 1995), it presents two case studies of voice construction by EFL learners in Iran. Through classroom observations, biographical and sociolinguistic interviews, and learner metalinguistic commentary, the study reveals how the two participants invest in two different voices that index their efforts toward the construction of a second language-mediated identity. The two learners are shown to gravitate toward informal and formal English words and use them in their speech in ways that are illustrative of how they envision their engagement with English both in the present and in the future. The pedagogical implications of the study are then discussed.