Positioning theory [van Langenhove and Harré (1999). Introducing positioning theory. In R. Harre, & L. van Langenhove (Eds.), "Positioning theory: Moral contexts of intentional action" (pp. 14-31). Blackwell Publishers] provides a useful analytical lens to examine how teachers' positioning in moment-to-moment interactions can expand or restrict opportunities for multilingual learners to participate in mathematical discussions and develop robust mathematical identities. In this study, I examined the discursive practices of one white, third-grade monolingual teacher, Keri, and the ways she interactively positioned Alexia, a Latina multilingual learner, in the first full month of the academic year during whole class interactions. Findings demonstrate Keri used a range of positioning acts to recursively position Alexia as a communicator of mathematics and mathematical thinker that simultaneously situated Alexia within the broader classroom storyline that successful mathematics students communicate their ideas to others. The findings confirm that monolingual teachers in elementary classroom settings appear to use similar positioning acts as bilingual teachers/teacher-researchers with individual multilingual students.