As one might imagine,
Korean is grammatically very different from
English. Obviously, I can't give an exhaustive description of
Korean grammar here, but here are the primary differences:
1) Instead of the basic English sentence structure subject-verb-object, Korean sentences always end with the verb, ie subject-object-verb. This is nice when you're learning the language, because it means that it's easy to pick out the verb.
2) Grammar is mostly contained in suffixes. Unlike English, where a lot of grammar is indicated by words like "to", "with", "that", etc., Korean uses suffixes like "-uro" "-reoh" "-nun" and so so forth for this purpose.
3) In English, every sentence (except imperatives) must have a suject. In Korean, the subject is often omitted, if it's obvious. In fact, everything obvious is omitted. In English, the response to a question like "What do you think of it?" would be "I like it!", whereas in Korean, the most common response would just be "Cho-ha-he-yo!", the equivalent of just saying "Like!"
4) There are many different levels of politeness in Korean. Aside from a few words that have an honorific and normal form, this mostly involves the verb suffixes. A verb with no suffix is just for your friends and inferiors, and is considered rude if used with anyone else. A common mid-level suffix is "-yo," used with people of a social status similar to your own, whom you don't know well. "-mneeda" or "-sumneeda" is a very formal verb ending, and is the one you would use when speaking to your boss or your grandfather, for instance.
An example: I am going to my house by car. Ja-dong-cha-ro jip-e ka-yo. Ja-dong-cha: car, -ro: by means of, jip: house, -e: to/at, ka: to go, -yo: middle politeness verb suffix. Note that the subject, "I" is omitted.