Hi,

I'm Ann. I've been teaching Korean students for almost three years now. I don't have an experience of teaching other nationalities except for Filipinos and Koreans, so I cannot give much comparison. But I'll try my best to describe Korean students according to my first hand experience with them.

Koreans are basically friendly people yet they are shy to speak up especially to a foreigner. Unlike other nations, they are not so open for foreigners. But nowadays, they are kinda changing. I bet you're an American. Actually Koreans are really fond of white people. They have a very high respect for Westerners especially if you're a native speaker of English.
Most Korean students aren't new to the language. In fact, most of them have been studying English for a long time already. But they don't use English in a daily conversation in Korea. They just study English but don't use it and that's the reason why a lot of them are still not profficient with the language. Speaking English to their friends is quite taboo and they are considered boastful if they do so. But one thing about them is that they are good at grammar. I learned from my students that in school, they learn grammar using the Hangul (Korean language). Their teachers explain grammar rules to them using Korean so they can understand better. But the bad thing about it is that they simply know the rules but don't know how to apply it and make grammatically correct sentences.

Korean students speak English with a monotonous tone. They are also having much difficulty with r and l, more than anything else.

Good luck..if you have more questions about Korean students, just feel free to contact me.