Gugyeol — 950? AD, Korea

Gugyeol "hol"

Gugyeol, also transliterated as Kwukyel,  and also sometimes called Tho, was developed to help convert Chinese literature into understandable Korean.  The Chinese characters and word order were preserved, but characters for word endings, particles, and some verb forms were tacked on to make the text more understandable for Koreans.

Unlike in Idu and Hyangchal, which used the standard Chinese characters “as is”, in Gugyeol, they frequently used a simplified character for the extra, Korean-specific characters (much in the same way that Hiragana and Katakana were simplified forms of the Manyogana glyphs).

Links: Wikipedia, A History of Korean Literature, Gugyeol glyphs, The Korean Language