This study explores teacher thinking through collaborative reflective dialogue. Research on teacher thinking is not new but there is little research available on the use of language as a socially-mediated tool to examine changes in teacher thinking over time. The work of Lev Vygotsky and John Dewey offer some guiding principles in this research. Vygotsky and Dewey suggest that teachers' articulated thoughts become tools for learning in a reflective dialogue practice. This dissertation addresses the following research questions: What happens to a teacher's thinking as expressed in spoken language, when engaging in a collaborative consultation practice? Do socially-mediated practices in collaborative consultation contribute to problem identification? If so, how? What kind of new learning can be documented for the teacher through the collaborative consultation process? Data for this qualitative research study comes from examining over 25 audio taped sessions between teachers who engage in a problem solving practice focused on student learning. Five cases of four to six sessions each were transcribed and coded looking for themes and patterns in language. These themes and patterns were categorized and analyzed as part of the qualitative inquiry in exploring teachers' thinking through changes in language over time. This study traces the history of research on teacher thinking in the early 1970's to current collaborative practices; (e.g., cognitive coaching, reflective dialogue, and collaborative consultation). Specifically, this dissertation examines previous work that supports a constructivist approach to learning for adults and children and contributes to the body of work on teacher thinking, reflective practice, and professional learning. The dissertation will have further implications for professional learning for educators. Setting aside time to think and process learning and teaching can be viewed as a form of staff development and professional growth. Indeed, looking within one's self, examining knowledge, beliefs, and assumptions through dialogue can cause changes in thinking over time. [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.]