This study is based on the "legitimate peripheral participation" theory by Lave and Wenger (1991). This field work focuses on the "learning (participation)" of three overseas students who enrolled a graduate school of engineering in Japan without possessing the adequate ability to communicate in Japanese. The process of their "learning (participation)" was studied, as was the type of Japanese ability that the three students found necessary. The study shows that in the first six months, there was no discernable difference among the three students in the study. However a comparison among the Japanese graduate students, they worked much more with and for other laboratory members, and took on roles similar to that of the lecturer in the laboratory. It is noteworthy that in this period, the three overseas students needed to use Japanese first, to ask about the proper laboratory procedures and second, when they needed to learn Japanese honorific expressions. After six months, a difference was noticed among the three overseas students. One of them had assumed a dominant position in the study group and had to play the role of the leader. This person needed to "teach/ explain", "direct", "consult with group members", "advice/instruct", "collect information", "consult with teachers and convey the result to other members of the group", "communicate to members outside the group", and "communicate about the members' personal lives". This study shows that even if an overseas student possesses only a basic level of the Japanese language, he or she can fulfill his or her roles in the laboratory by learning the Japanese expressions required to lead a group and the other members of the group can succeed in their studies. This process promotes "learning (participation)".