Korean is the native language. Most people speak very basic English. Although I'm in the largest city in Seoul, there are people from all over the world here who speak different languages. All the street signs in Seoul are in both English and Korean. Most restaurants often have an English menu. Whenever you order food at a kiosk at a cafe or restaurant, there are often multiple language options. The most common options are English, Japanese, and Korean. A lot of signs in buildings are also in both English and Korean. If you were to travel to the countryside, the signs would be in only Korean.
The currency in Korea is South Korean won. The lowest bill is 1,000 won, which is $0.68. Then it goes to 10,000, which is $6.80. Then the highest bill is 100,000 won, which is $680. So imagine everything is about 30% off with the currency conversion. Pretty nice right!
A bottle of water can cost 1,000 to 3,000 won. In dollars, that would be $0.69 - $2.07. You can buy a bottle of water at the convenience store. Convenience stores are everywhere in Korea. When I mean everywhere, no matter where you are, there is probably a convenience store within 1 minute of walking distance from you.
