The observational and interview study explored how two middle school teachers, Ms. Watson and Mr. Garry, from two different public schools in a small college town in a midwestern state in the United States, used talk moves to establish mathematical discussions during both small group and whole class discussions. The study also examined their perspectives on leading discussions and on using talk moves in order to accomplish particular goals. To explore how these two teachers utilized talk moves to facilitate discussions in their classrooms, observations of an entire instructional unit were collected for one class of students for each teacher; the unit for each teacher focused on three-dimensional geometry. Five teacher interviews--an initial teacher interview, a periodic interview, a follow-up interview in person, a follow-up interview via Zoom, and a follow-up interview via email--were conducted with each teacher to elicit their perspectives on using their talk moves and more broadly on leading mathematical discussions. To elicit students' perspectives on their teachers' use of some talk moves, for each classroom, a student focus group interview was also conducted with six students who demonstrated a range of participation and performance on the unit test. Findings revealed that both Ms. Watson's talk moves and Mr. Garry's talk moves could be categorized into 5 themes: Inserting the Teacher's Mathematical Ideas into the Conversation, Supporting Student Understanding about Tasks and Learning Goals, Amplifying Students' Ideas, Promoting Student Participation, and Eliciting Student Thinking via Questions. Ms. Watson and Mr. Garry utilized some common talk moves, but some of the talk moves within each theme differed for the two teachers. Although they used some common talk moves, how they used some of them and their perspectives on using them differed. These two teachers used their talk moves for several purposes, including to learn students' mathematical thinking, to ensure the teacher's interpretations of students' ideas, to promote students' participation in discussions, and to encourage students to communicate their mathematical thinking with other participants in discussions. The two teachers also demonstrated some unique, personal talk moves that they used for building relationships with their students. Limitations of the study and recommendations for future studies are discussed. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]