Cross-generational vowel changes in Gyeongsang Korean*

This study investigates vowel changes in South Gyeongsang Korean, focusing on the /ʌ/-/ɨ/ split and the /o/-/u/ merger across four age groups: children, teenagers, young adults, and elderly speakers. The objective is to identify whether these changes exhibit a continuous age-related progression, an adolescent peak, or reflect influences from external dialects, such as Seoul Korean. A total of 37 native speakers produced target vowels in a CVCV format, with acoustic measurements (F1 and F2) taken at the vowel midpoint. The results reveal a discontinuous pattern of change across generations, with young adults demonstrating the most innovative phonetic patterns. Contrary to the notion of an adolescent peak, young adults, rather than adolescents, led the /ʌ/-/ɨ/ distinction and the chain-like shift in /o/-/u/, likely due to increased exposure to Seoul Korean. Despite this external influence, Gyeongsang speakers adapted the changes internally, lowering /u/ instead of raising /o/, thereby maintaining a balanced vowel system. The findings position young adults as primary agents of phonetic innovation and illustrate how external linguistic influences and internal phonetic structure together shape the evolution of regional dialects.