Responding to concerns raised by grade 11 mathematics students, we examined a broad set of mathematics classroom transcripts from multiple teachers to examine how the word "just" was and could be used to suppress and invite dialogue. We used corpus linguistics tools to process and quantify the large body of text, not to describe the nature of the discourse, but rather, in the tradition of critical discourse analysis, to prompt reflection on a range of possibilities for directing classroom discourse. We found that the word "just" was one of the most common words to appear in these classrooms. Drawing on Bakhtin's ("The dialogic imagination." Austin: University of Texas Press, 1975/1981) distinctions between monoglossic and heteroglossic utterances, we found that the word "just" acted as a monoglossic tool, closing down dialogue. We propose, however, that "just" can also be used as a heteroglossic tool as it can focus attention and thus invite dialogue.