This thesis contains the analysis of Korean characteristic in Twitter. This thesis also discussing the code switching and code mixing in Twitter.The aim of the research is to describe variance of linguistic characteristic used by Korean teenagers. The source of the data used in this research is10 twitter accounts of Korean teenagers between 15-20 years old.The technique of the research is conducted by data identification in status transcription and conversation, classification, and analysis according to the problem formulation. The result of the analysis indicate that 1) there are font changes in vocals and consonant, 2) there are syllables changing, 3) there are font omissions, 4) there are syllables omissions, 5) there are word simplifica...