Sejong the Great
Before the creation of Hangul, people in Korea (known as Joseon at the time) primarily wrote using Classical Chinese alongside phonetic writing systems based on Chinese script that predated Hangul by hundreds of years, including idu, hyangchal, gugyeol, and gakpil. However, due to the fundamental differences between the Korean and Chinese languages, and the large number of characters that needed to be learned, there was much difficulty in learning how to write using Chinese characters for the lower classes, who often lacked the privilege of education. To assuage this problem, King Sejong created the unique alphabet known as Hangul to promote literacy among the common people. His intention was to establish a cultural identity for Korea through its unique script.
Origin of Hangul
Although several of the basic concepts of the Korean alphabet were inherited from Indic phonology through the ’Phags-pa script, such as the relationships among the homorganic consonants and, of course, the alphabetic principle itself, Chinese phonology played a major role. Besides the grouping of letters into syllables, in functional imitation of Chinese characters, according to Ledyard it was Chinese phonology, not Indic, that determined which five consonants were basic, and were therefore to be retained from ’Phags-pa. These included the plain stop letters, ꡂ "g" for ㄱ "g" , ꡊ "d" for ㄷ "d" , and ꡎ "b" for ㅂ "b" , which were basic to Chinese theory, but which represented voiced consonants in the Indic languages and were not basic in the Indic tradition. The other two letters were the plain sibilant ꡛ "s" for ㅈ "j" (ㅈ was pronounced in the fifteenth century, as it still is in North Korea) and the liquid ꡙ "l" for ㄹ "l" .