Lenition of Lenis Obstruents in Seoul Korean Spontaneous Speech

Abstract

Lenis obstruents in Seoul Korean have frequently been described as intervocalically voiced and shorter in phrase-medial position, but reduction, i.e., a shallower change in intensity, has not been studied as thoroughly. This paper investigates all three of these acoustic properties of lenis obstruents in a spontaneous speech corpus. It demonstrates that lenis obstruents are optionally voiced in Accentual Phrase medial position. However, exceptionally voiceless Prosodic Word (PWd) medial tokens are nonetheless reduced and shorter, than the phrase-initial tokens. Prosodic conditioning of the acoustic realization of lenis obstruents exemplifies `continuity lenition', signaling a continuation of the prosodic constituent. Considering all three acoustic properties of lenis obstruents, prosodically conditioned `lenition' may not be optional in the phrase-medial position. This study also shows that when an underlying coda lenis obstruent is resyllabified to an onset position within a PWd, it is more lenited compared to a token that originates in a syllable onset position. Mediation analyses of the causal relationship between the three phonetic reflexes of the prosodic context–voicing, intensity reduction, and duration–show that the changes in voicing and intensity are not fully mediated by the change in duration, contrary to previous studies exploring continuity lenition patterns. These results are discussed in relation to the potential difference between the phonetic implementation of domain-initial strengthening and domain-medial lenition (or `continuity lenition'). While the former is instantiated by a change in duration which then affects other acoustic qualities (voicing and intensity), the latter can occur without a change in duration.

Keywords: Seoul Korean, Continuity lenition, Lenis voicing, Spontaneous speech corpus, Mediation analysis, Phonetics-prosody interface