This investigation examined interactions in three classrooms to determine how they influenced Discourses related to mathematics learning and teaching. Mathematics education literature suggests that effective mathematics instruction includes mathematical Discourses. However, effective mathematical Discourses within mathematics classrooms vary widely and effective Discourses in one classroom may be ineffective in another. The purpose of the investigation was to gain insights for developing effective Discourses or classrooms that exhibit reform oriented cultures (ROC). The primary research question addressed was how do classroom interaction influence the Discourses related to mathematics learning and teaching in MCP supported classrooms? MCP supported classrooms are within buildings were an MCP instructional coach is assigned. The MCP coaches' role within the building includes: (a) developing his or her knowledge and understanding of research-based mathematics education reform; (b) providing sustained classroom-embedded professional development to small groups of mathematics teachers; and (c) offering school-based professional development for all mathematics teachers in the building. supported classrooms? [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://www.proquest.com/en-US/products/dissertations/individuals.shtml.]