king sejong the great. the most revered korean king, sejong invented hangeul, the korean alphabet, which is widely considered to be one of the best phonetic systems ever created. since traditional chinese characters were too difficult for common people to learn, most koreans were functionally illiterate before hangeul's creation in the 1400's. what is perhaps most fascinating is that the shape of the letters mimic the shape of the mouth and tongue in the production of that sound. due to its simplicity and phonetic consistency, most people can learn the korean alphabet and sound out words within a couple hours; however learning to understand what you're actually reading takes quite a bit longer!