37.583; 127 Official language(s) Korean Official scripts Hangul [ 1 ] Ethnic groups   Korean (99%) [ 2 ] Demonym South Korean, Korean Government Unitary presidential constitutional republic  -  President Lee Myung-bak  -  Prime Minister Kim Hwang-sik  -  Speaker Kang Chang-hee Legislature National Assembly (Gukhoe) Establishment  -  National Foundation Day October