With the Ministry of Education, Sports, Science and Technology calling for junior and senior high school English classes in Japan to be more communicative and taught in English, teachers need effective tools to help make their classrooms more interactive. Cooperative learning activities have the potential to increase interaction among students and to work well in creating a communicative learning environment. In this paper, we review some basic concepts of cooperative learning and present a list of useful English expressions that we have developed to aid students as they engage in cooperative learning activities. Findings are given after using the list for 22 months in a private, all-girls secondary school in Japan which suggest that the list contributed to smoother interactions amongst students, as well as increased student motivation and confidence.