The aim of this paper is to study the modern natonal language history on the early seventeen century, being examined the phonetic character of WonSeong area through the Koraeeunhae. The method compared this book with the others on the same period. First of all so as to study phonetic character. I examined the character inscription. This book character reflected the grammatical consciousness which wanted to reveal the conservative inscription and the actual language. Specially it used the language of Korea own together with the Chinese word, as much as possible, here the consciousness of Chinese inscription were reflected. `-ki` the inflexion of noun alternated `-yeum` the inflexion of noun at this times. This book which abbreviated the ending of a word suggested the spoken language style sentence. In the division of a declaration, the book fewer than the sohakeonhaegot a lot of. `、` the confusion of declaration appeared even in the noset. The next phonetic character did not see the initial rule but the initial rule was saw in the case of Chinese the initial rule which transferred to ㄹ>ㄴ were saw. The consonant hamony only appeared before`ㄴ`. It would be a lot of realization but only appeared several of vocabulary. The collapse of vowel harmony appeared but were not severe. First of all immediate cause is change of `、`. Today, the heavy sound phenomenon is common phonetic shape but this book used heavy sound phenomenon together with common sound. In an inflected word or an uninflected word the onset were appeared the heavy sound, but the Chinise heavy sound was never discovered.