The emergence, progress, and impact of sound change in progress in Seoul Korean: Implications for mechanisms of tonogenesis

This study examines the origin, progression, and impact of a sound change in Seoul Korean where the primary cue to a stop contrast in phrase-initial position is shifting from VOT to f0. Because it shares similarities with the initial phase of tonogenesis, investigating this “quasi-tonogenetic” sound change provides insight into the nature of the emergence of contrastive f0 in “tonogenetic” sound changes more generally. Using a dataset from a large apparent-time corpus of Seoul Korean, we built mixed-effects regression models of VOT and f0 to examine the time-course of change, focusing on word frequency and vowel height effects. We found that both VOT contrast reduction and f0 contrast enhancement are more advanced in high-frequency words and in stops before non-high vowels, indicating that the change is spreading across words and phonetic contexts in parallel. Furthermore, speakers suppress non-contrastive variation in f0 as f0 emerges as a primary cue. Our findings suggest that one impetus for tonogenetic change is production bias coupled with an adaptive link between the cues. We further discuss the role of Korean intonational phonology on f0 which may help explain why the phonetic precondition leads to change in Seoul Korean but not in other languages.