I spent a summer there in late 1980s (yeah, I'm old). I only learned the essential phrases of please, thank you, hello, and Where's the bathroom. Fortunately most Koreans learn English in high school. Though some of it is as bad as our high school French.

That being said, good luck with learning the language. I understand there are only 24 letters and they are always pronounced the same way. So you can learn how to pronounce things without knowing what you are saying.