In this study, it was intened to infer the vowel system in Gyeongsang-do dialect of the 16th century from /?/,/ㅔ/,/ㅐ/,/-/,/ㅓ/,/ㅟ/,/ㅚ/ whixh are thought to have caused them. In conclusion, it has been found out as follows. First,/?/ functioned as a phoneme both in the first syllable and the non-first syllable. Second,/?/>/l/ was a voluntary alternation of phonems. Third, /ㅔ/,/ㅐ/,ㅟ/,/ㅚ/ were practically realized into /aj/, /αj/,/uj/,/oj/. Fourth, there were indications that /ㅔ/,/ㅐ/ were realized into /e/,/ε/. Fifth, /ㅡ/,/ㅓ/ were clearly distinct both in the first syllable and the non-first syllable. On the basis of the above, the vowel system in Gyeongsang-do dialect of the 16th century could be concluded as follows.
The Vowel System in the 16th century`s Gyeongsang-do Dialect( *means that there is a possiblity of having been realized.)
