These letters are Hangul, the Korean alphabet. Hangul is very scientific and easy to learn so you can actually read and write in Korean in a short time although it will take more time to understand it. Try to learn Hangul! It's really easy :D
"Korean alphabet. For over a millennium, Korean was written with adapted Chinese characters called hanja, complemented by phonetic systems like hyangchal, gugyeol, and idu. In the 15th century, a national writing system called hangul was commissioned by Sejong the Great, but it only came into widespread use in the 20th century, because of the yangban aristocracy's preference for hanja."