Purpose: The aim of this study is to explore teachers’ experience and understanding of classroom communication after participating in a speech-language pathologist (SLP) led in-service training on classroom communication. Method: This qualitative study used a focus group approach to explore how teachers describe their classroom communication. Twenty primary-school teachers participated. Thematic analysis was used to analyze the teachers’ responses about their classroom communication practices 6 months after in-service training. Results: Three core themes on teachers’ understanding of their communication in the classroom were identified in the analysis: (1) awareness of voice use; (2) the use of body communication; (3) setting the stage for learning. The teachers gave many examples of voice use reflecting an increased awareness of audibility and vocal health. They reported on moving around more and using more body communication to enhance their message. Further, they expressed an increased awareness about how body posture affects voice and communication. The third theme reflects how the teachers “sets the stage for learning” i.e. how they use the prerequisites in the physical environment for successful classroom communication, including the classroom’s sound environment as well as seating and furniture. Conclusions: The findings in this study indicate that teachers increased their awareness, implemented new practices in their classroom communication and reflected on prerequisites for classroom communication as a result of the in-service training. Teachers’ classroom communication developed when provided practical training and strategies to increase their awareness on communication. We conclude that this type of SLP-led training can be recommended as in-service training.