Korea
Hangul Day (also spelled as Hangeul Day) is a day that celebrates the creation of the Hunminjeongeum (Hangul, Korean alphabet), which was inscribed to the UNESCO Memory of the World Register in 1997. Hangul was created by Sejong the Great in 1443 and proclaimed in 1446. 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. Hangul Day was founded in 1926 during the Japanese occupation by members of the Korean Language Society, whose goal was to preserve the Korean language during a time of rapid forced Japanization. Today, both South Korea and North Korea celebrate Hangul Day as a national holiday.Sources
Origin of Hangul
Of these seven vowel sounds, three could not be iotized (preceded by a "y-" sound). These three were written with a single stroke: ㅡ "ɨ," ㆍ "ʌ," ㅣ "i." (The letter ㆍ "ʌ" is now obsolete except in Jeju dialect.) The "Hunmin Jeong-eum" states that the shapes of the strokes were chosen to represent the Confucian 三才 "sāncái" "three realms" of 天 heaven, a "yang" concept, represented with a dot for the sun, ; 地 earth, a "yin" concept, represented with a flat line, ; and 人 man, represented with an upright line, , who mediates between the two. The other four vowels, which could be iotized, were written as a dot next to a line: yin ㅓ "ə" and yang ㅏ "a" (which alternate under vowel harmony), yin ㅜ "u" and yang ㅗ "o" (which also alternate). Iotation was then indicated by doubling this dot: ㅕ "yə," ㅑ "ya," ㅠ "yu," ㅛ "yo."
There was presumably a third parameter in designing the vowel letters, not mentioned in the "Haerye," namely choosing horizontal ㅡ "ɨ" as the graphic base of "closed" (rounded) ㅜ "u" and ㅗ "o," and vertical ㅣ "i" as the base of "open" (unrounded) ㅓ "ə" and ㅏ "a." The horizontal letters ㅡㅜㅗ "ɨ u o" represented back vowels in the fifteenth century, as they do today, whereas the fifteenth-century sound values of ㅣㅓㅏ "i ə a" are uncertain. Some linguists reconstruct them as , respectively (and reconstruct obsolete ㆍ "ʌ" as ); others as (with ㆍ "ʌ" as ). In the latter case, the vertical letters would have represented front vowels, the dot the sole central vowel, and the vowel harmony, described as "shallow" vs "deep", would have been one of vowel height, with the "yang" vowels lower than their "yin" counterparts.