The practice of cooperative learning has already been popular in Japan. It is recently being criticized, however, that it is becoming a mere name without essential practices. A major cause of this problem would be an unclearness of the mechanism of cooperative learning. What is occurring when children cooperate with others? Why do children need relations with others in order to construct a knowledge? Th answer these questions, this paper tries to clarify the contents of social constructivism which is a theoretical basis of cooperative learning, with focusing on a problem of language. This paper consists of three parts: 1) the problem of 'What is language?" (section 4). The nature of language was summarized from the theory of Ferdinand de Saussure, which was interpreted by a Japanese linguistic philosopher MARUYAMA Keizaburo; 2) the problem of construction mechanism (section 5). The relationship between language and knowledge was considered through Maruyama's cultural theory; and 3) a consideration of the contents of learning theory of social constructivism with arguments in section 4 and 5 (section 6). The conclusion shows the points as follows: 1) we can understand that formation, creation and rectification of "the individual representation of Jangue' is learning; 2) a mixture of palore in cooperative learning transfigures the individual representation of Jangue, 3) we need a complex of multiple palore because language has a nature of arbitrariness; 4) therefore, the interaction between students in cooperative learning plays a role of a sense generation.本稿は、第76回日本教育学会(2017年8月26日 桜美林大学)での口頭発表に基づいている