South Korean communicate using the same language is Korean, the language of the majority, "Han Kook-mun" or "Han Kook" in Seoul and the metropolitan area is used as a common language. The local language is also used by various sectors. Still, the South Koreans were able to understand each other well. Except dialect of Jeju Island. The elusive than other localities.
A Korean alphabet, called "Hangeul" is literally the King Sejong invented consists of 14 consonants and 10 vowels which can be combined into syllables and words are plenty. Hangul has been hailed as a character invented by the most scientific. A character can learn and easy to understand.