Agglutinization

Agglutinization is a fancy word for "sticking things together with duct tape." Koreans don't conjugate (is, am, was, were, been, being), and they don't decline (I, me, my, mine). Rather, they stick things on the ends or occasionally the beginning of the words they use to get the meaning they want.

In the process of making things stick, sometimes some changes have to be made. Sounds have to be stuck in between, final or initial sounds have to modify, etc... The rules are rather simple, though, and in practice, you'll find that you don't have to think about them much if at all.

If you think hard enough about the way things are in Korean, you can usually uncover patterns that stretch all across the language. What you will see is a language that is extremely flexible. It's really a system with a few core words and concepts and a ton of vocabulary thrown on top.