Jang, Hyejin, Shin, Jiyoung, and Nam, Hosung. 2015. 서울 방언 단모음의 연령별 실현 양상. Studies in Phonetics, Phonology and Morphology 21.2. 341-358.

This study aims to investigate the acoustic properties of monophthongs from Seoul speakers in their 20s through 60s. Results show that (1) speakers in their 60s exhibit a greater spectral difference between /e/ and /ɛ/ than the other age groups; (2) /ɯ/ is more fronted in speakers younger than 60; (3) more fronting of /ɯ/ is observed in speakers in their 20s than older groups with respect to /a/; and (4) no significant difference is found between /o/ and /u/ in all age groups. (Korea University)

Keywords: monophthongs, Seoul dialect, age, first formant (F1), second formant (F2), Euclidean distance, slope