The purpose of this mixed-design study was to examine the impact of three types of professional development activities aimed at improving conversations in four targeted preschool classrooms. A review of the literature was used to identify the professional development approaches and the importance of improving teacher-child conversations as a resource for enhancing children's language and communication development. The four teachers in these preschool classrooms were provided a traditional workshop, a modeling session, and a self-reflection/feedback session over a 5-month period. To examine teachers' conversational strategy use and children's language, data were collected before the interventions and at each phase. Data included initial and culminating teacher interviews, post-professional development questionnaires, and videotapes of teachers and children engaged in conversations during thirty minutes of playtime in each classroom. Transcripts from the teacher interviews and passages from the teacher questionnaire responses were coded and analyzed to examine the teachers' perceptions of the effectiveness of each of the three professional development sessions. Transcripts of teacher-child conversations were coded using four major code categorizations (super codes). Frequency counts of teachers' use of conversational strategies and children's responses and initiations were calculated. The results were compared from phase to phase to examine the impact of each type of professional development session and all three sessions cumulatively. Differing profiles emerged, showing variation in improvements and lack of improvement across the strategies for each phase and overall. However, group data, taken cumulatively, showed overall improvement in teachers' use of conversational strategies and in children's language. Teachers found each of the professional development experiences to provide different perspectives. The quantitative analysis supported these findings in showing that teachers improved in their conversational strategies with children over the five-month period. Overall, findings indicate that professional development approaches exist that may be effectively employed to improve teachers' conversations with young children. [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.]