This study aims to examine and discuss Korean adolescents’ oral language culture, based on the results of the survey from 3,429 adolescents, ranging from 10 to 18 years old, which was conducted by National Institute of Korean Language. Researchers defined the adolescents’ language culture as a hierarchical structure which consists of three layers, namely, expression, behavior, and thought. Unlike previous studies which have focused on the expression layer, this study tries to focus on the behavior and thought layer of adolescents’ language culture. Researchers selected four categories-two are from behavior layer, and another two are from thought layer-as the locus which Korean adolescents’ oral language culture shows its unique characteristics: (a) Active Participation in Public Communication(APPC); (b) Empathic Attitude in Private Communication(EAPC); (c) Recognition of Language as Self-Expression(RLSE); and (d) Recognition of Communication Role Model(RCRM). And Researchers analyzed the difference of survey result by school year, sex, and scale of residential area. The findings are as follows: (1) There is decreases in three cultural aspects, including APPC(public speech and discussion), EAPC(with parents), and RCRM; (2) There is difference between male and female adolescents in three cultural aspects, including APPC(discussion), EAPC(with peers), and RLSE. Female adolescents where higher than male in all cultural aspects; (3) There is difference among metropolitan, urban, and rural adolescents in three cultural aspects, including APPC(public speech and discussion), EAPC(with peers and with parents), RLSE. In all cultural aspects, metropolitan adolescents were higher than urban and rural adolescents or than rural adolescents. Some general discussions were given in conclusion.