I totally agree with the two previous answers. The accents are different, the usage and expressions are different. Also, I would like to add - in general the level of politeness seemed to be different too. Chinese Korean seemed to use Formal Polite Speech more often and South Korean seemed to use Casual Polite Speech more often(They still use formal polite speech for the right occasions though) Also, because of American influence, the South Koreans tend to use a lot of English words(with a korean accent) in their daily Korean conversation. If you don't believe me , you can go to veoh.com and watch the korean drama Pure 19 - its about the trials and tribulations of a Chinese Korean girl who got married and landed in Seoul.Oh, I almost forgot , the Korean spoken in North Korean is quite different ,too. North Korean government has a policy of eliminating Chinese words from their language whereas in South Korea they don't mind mixing their language with a lot of Chinese words and American English words. That's why it is easier for us Chinese to learn Korean. ;-) (KogchongHajimaseyo, Hangpokaeseyo) Hope it helps, give me a shout. ;-)