Yes, I think it is possible, but you have to almost pretend to live in that country -- while living where you are. For example: change your phone's language to English/Korean, only listen to music in those languages, watch or listen to the news mostly only in those languages, only read in those languages...and talk a lot, both to others and to yourself in those languages. Almost put yourself mentally and linguistically in the places where those languages are spoken.
I know of people who have done that (total emersion at home) and they have become VERY good at their target language. Fluency is a subjective thing. It always depends on many factors if you can speak without hesitation and with (mostly) correct grammar. I can speak fluently about what I ate for breakfast in Italian, but not about the problems following earthquakes in rural Italy. It all depends on your goals.