HunMinJeongEum-훈민정음-訓民正音
Publication at Chosun dynasty, which was king SeJong's (세종대왕) motivation and love to his own people.
The people living in that dynasty knew how to read and speak, but wasn't able to write.
SeJong saw this as a serious problem, since this may lead to misunderstanding between market vendor while trading. Also he wanted to show his love and care to those people all around the country, so he stood in the peoples state and pointed out problems.
Primary language after this publication was Chinese mixed with Korean letters. Hanja and Hangeul.
Nowadays, this publication led Korean people to speak Korean language.
The first paragraph of the document reveals King Sejong's motivation for creating hangeul:
"The language of [our] people is different from that of the nation of China and thus cannot be expressed by the written language of Chinese people. Because of this reason, the cries of illiterate peasants are not properly understood by the many [in the position of privilege]. I [feel the plight of the peasants and the difficulties faced by the public servants and] am saddened by the situation. Therefore, twenty eight [written] characters have been newly created. [My desire is] such that, each [Korean] person may become familiar [with the newly created written language of Korean] and use them daily in an intuitive way."
(Source:Wikipedia, the free encyclopedia)
Paragraph rendered into written Korean (Eonhaebon):
