This study aims to understand the theory of didactic transpositionand to analyze textbooks which contain transformed knowledge, witha view to knowing various possibilities of the transposition of knowledge. Education about the history of Korean language, which is a sectorclearly characterized by knowledge among Korean language textbooks,is appropriate for an examination of how academic knowledge has beenchanged into teachable knowledge. This study compares the contentsof the history of changes of Korean language in authorized textbooks interms of didactic transposition, so as to investigate how academic knowledgeand knowledge presented in curriculums has been changed byauthors of textbooks into teachable knowledge. It is expected that thisstudy will be subservient to moving ‘knowledge of the history of Koreanlanguage which is to be taught in school grammar’ in a right direction.