Yanbian Korean speakers tend to merge /e/ and /ɛ/ when exposed to Seoul Korean

This study examined the vowel merger between the two vowels /e/ and /ɛ/ in Yanbian Korean. This sound change has already spread to Seoul Korean, particularly among speakers born after the 1970s. The aim of this study was to determine whether close exposure to Seoul Korean speakers leads to the neutralization of the distinction between the two vowels /e/ and /ɛ/. We recruited 20 Yanbian Korean speakers and asked them about their frequency of exposure to Seoul Korean. The exposure level of each participant was also recorded using a Likert scale. The results revealed that speakers with limited in-person interactions with Seoul Korean speakers exhibited distinct vowel productions within the vowel space. In contrast, those with frequent in-person interactions with Seoul Korean speakers tended to neutralize the two vowels, displaying considerably overlapping patterns in the vowel space. The relationship between the level of exposure to Seoul Korean and speakers’ vowel production was statistically confirmed by a linear regression analysis. Based on the results of this study, we speculate that the sound change in Yanbian Korean may become more widespread as Yanbian Korean speakers are increasingly exposed to Seoul Korean.