Hangul Day
Before the creation of Hangul, people in Korea (known as Joseon at the time) primarily wrote using Classical Chinese alongside native phonetic writing systems that predate 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 needed to be learned, there was much difficulty in learning how to write using Chinese characters for the lower classes, who often didn't have the privilege of education. To assuage this problem, King Sejong created the unique alphabet known as Hangul to promote literacy among the common people.
Origin of Hangul
The five adopted letters were graphically simplified, retaining the outline of the ’Phags-pa letters but with a reduced number of strokes that recalled the shapes of the speech organs involved, as explained in the "Haerye." For example, the box inside ’Phags-pa ꡂ "g" is not found in the Korean ㄱ "g" ; only the outer stroke remains. In addition to being iconic for the shape of the "root" of the tongue, this more easily allowed for consonant clusters and left room for an added stroke to derive the aspirated consonant ㅋ "k" . But in contrast to the "Haerye" account, the non-stops "ng" , ㄴ "n" , ㅁ "m" , and ㅅ "s" were derived by "removing" the top stroke or strokes of the basic letters. (No letter was derived from ㄹ "l" .) This clears up a few points that had been problematic in the "Haerye." For example, while it is straightforward to derive ㅁ "m" from ㅂ "b" by removing the top of ㅂ "b" in Ledyard's account, it is not clear how one would derive ㅂ "b" by adding something to ㅁ "m", since ㅂ "b" is not analogous to the other stops: If ㅂ "b" were derived as in the "Haerye" account, it would be expected to have a horizontal top stroke similar to those of ㄱ "g" , ㄷ "d" , and ㅈ "j" .