In this study, the authors aimed to develop lessons in which diversity, collaboration , and authentic learning are ensured through children’s cooperative involvement in a special class for students with intellectual disabilities. The authors framed three practices and analyzed children’s activities and the teachers’ environment setting , including music and body movements. The authors found three key results. First, the ability to recognize the diversity of body movements and expression in different contexts was improved in the practices which caused authentic learning. Second, collaborativeness promote s and nurture s cooperation (sharing roles) when children and teachers work together to achieve collaboration (creation by synergistic effect), finally realizing authentic learning. Third, music and body movements have the power to communicate what words are often unable to－the ability to make others feel that they are wanted and valued. Music and body movements served as the medium and catalyst for deepening authentic dialog.