While poking around on IMDB, I found this interesting little bit of Lost trivia:
Due to his childhood in America, Daniel [Dae Kim] knew very little Korean before he did “Lost”. He has said that his co-star on that show Yoon-jin Kim, who is fluent in both English and Korean, has been invaluable in coaching him on his Korean, which has apparently improved. Ironically, to the audience’s knowledge, Daniel’s character knows nothing but Korean.
Just in case I haven’t mentioned it before, Daniel Dae Kim is a pleasure to behold. If I were to channel Homer, I’d say: “He appears comely like a god amongst mere mortal men.” If I were to channel The Cure, I’d say: “Hot Hot Hot!”