Using classroom observation and video recording methods, we performed a comparative study on the forms and content of dialogues in the classrooms between expert and novice teachers. Of the 55 lessons surveyed, it was found that expert teachers tend to use analytical and comparative questions more frequently to detect students' mathematical reasoning. Students and teachers work together to determine the answer to a question and the dialogue in the classroom takes place in a way that students present an answer, the teacher and the other students question the answer, and then the students explain the answer. On the other hand, a novice teacher often tends to give students hints, or utilize simple questions to jog the memory. The novice teacher recognizes students' logic but does not incorporate them into his/her teaching. In this case, the teacher becomes the sole judge for the appropriateness of the answers and the typical dialogue in the classroom occurs in a way that the teacher asks a question, students answer, and the teacher comments.