The paper contextualizes the concepts of dialogue and dialogism, as outlined by Bakhtin’s framework, in the fields of second language acquisition and applied linguistics. Specifically, it shows how dialogism could be applied to three distinct, but interconnected contexts: the context of immigrant second language learners, second and foreign language teacher education, and the increasingly important area of English as an international language. The paper argues that viewing language learners’ and their teachers’ identities as dialogic constructions and, particularly, the texts they produce as examples of active dialogic activities can help researchers and practitioners understand the active, agentive nature of the process of language acquisition better.