This dissertation presents a study aimed at exploring the influences on language learners' contributions to dialogic classroom interaction in a Japanese university EFL (English as a foreign language) classroom context. Dialogic approaches to teacher discourse rely on the contributions of students to classroom interaction as well as the interpretive skills of teachers to facilitate understanding and co-construction of knowledge. However, the contemporary literature has reported on challenges involved in fostering mutual classroom dialogue with language learners, owing to challenges with linguistic and academic resources and differences in culturally informed perceptions regarding academic roles and expectations. This paper explores the need for teachers and researchers to identify (1) shifts in pedagogical practices that occur during the course of discrete episodes of classroom discourse, (2) the possible causes that prompt such shifts, and (3) the power dynamics surrounding such shifts. The study engages in observations of an EFL classroom and interviews with classroom participants. In conjunction with discourse analysis and critical discourse analysis, this study will employ discussions of instructional conversation (Goldenberg, 1992), challenges to dialogic interaction (Engin, 2017), and "bases of social power" (French & Raven, 1959) to understand how an L1 English-speaking teacher adjusts their pedagogical practices in response to L1 Japanese students' contributions to classroom discourse. The findings of this study indicate that the teacher's instructional shifts take advantage of various interactional resources, opportunities for co-constructing meaning, and validation of students' knowledge and sociocultural identities in order to build a productive dialogue within the classroom. Ultimately, this dynamic classroom environment provides pathways for fostering rapport with and agency in students, two qualities that the contemporary research has associated with positive learning outcomes. Discussion of the discursive practices explored in this study should prompt researchers of and practitioners in language classroom contexts to transcend formulaic approaches of "teacher talk" and elicitation of language for its own sake. Instead, the attribution of rapport and mediated agency to dialogic interaction realized through instructional shifts necessitates a paradigm shift in the contemporary empirical research in language education toward a more sociocultural approach to understanding mediation between classroom interactants across differences of language and culture.