The notion that "immersion" in a country will enable you to speak it's language is an interesting one and one which most people would feel intuitively to be correct. However, there are caveats to this theory, which I don't have time to go into now. I will merely point out that it is possible to recreate your own language "immersion" using your own resources and the internet. As with all things, it comes down to the determination of the learner to make the best use of what is available to them.

I agree that (for me anyway) that going to South Korea to learn Korean helped a lot. Mainly it helped me figure out what I needed to learn - directions, anything ordering food and food in general and how to ask questions (what is this? can i ask you a question etc.) However, I don't think it will work for everyone, it comes down to how you learn. If I had no understanding of Korean before I went, I would of struggled a lot. So going in without basic fundamentals may not improve your language skills. It also depends on how active you are in the language. Where I live and go to university, many international students, especially from Asia usually don't put themselves out there to meet native English speakers. Not to mention, in Australia entire suburbs are dominated by bilingual signs and shops. Sydney CBD is like walking into a foreign film (awesome for me, but I don't think it helps international students though). That's just my thoughts, and everyone is different.