This book is the first to explore the constitution of language learner agency by drawing on performativity theory, an approach that remains on the periphery of second language research. Though many scholars have drawn on poststructuralism to theorize learner identity in non-essentialist terms, most have treated agency as an essential feature that belongs to or inheres in individuals. By contrast, this work promotes a view of learner agency as inherently social and as performatively constituted in discursive practice. In developing a performativity approach to learner agency, it builds on the work of Vygotsky and Bakhtin along with research on 'agency of spaces' and language ideologies. Through the study of discourses produced in interviews, this work explores how immigrant small business owners co-construct their theories of agency, in relation to language learning and use. The analysis focuses on three discursive constructs produced in the interview talk--subject-predicate constructs, evaluative stance, and reported speech--and investigates their discursive effects in mobilizing ideologically normative, performatively realized agentive selves.