This study aims to compare and analyze the language use patterns among Koreans in the Korean communities in North and South America. It is important to survey attitude, environment and use patterns concerning the Korean language in both groups to understand how the language is changing and transcending as a mother tongue. The survey data was collected in major residental locations of Koreans in the US, Brazil, Argentina, and Paraguay. The analysis of topic related to language attitude and perception, language proficiency, and language use environment showed that Korean-South Americans were higher Korean proficiency than Korean-North Americans. Especially, in the case of the 2nd generation groups, the Korean-South Americans showed a stronger proficiency in the Korean language use. Korean immigrants in both areas have a immigrant history jointly, however, the current social, economic and educational systems and policies could affect the language choices and change of Korean immigrants in both areas. Based on the results of this study, the future use of Koreans are predicted in both areas. (Yonsei University)