Structured Speaker Variability in Spontaneous Japanese Stop Contrast Production

Abstract

Studies of speaker variability in the realisation of stop voicing contrasts have demonstrated that differences across speakers are highly structured both within and across phonetic categories. These studies have focused on languages with similar voicing systems in scripted speech; it remains unclear how stop realisation varies in spontaneous speech more generally. This study examines speaker variability in two acoustic cues to stop voicing–Voice Onset Time and Voicing During Closure–in a corpus of spontaneous Japanese, a language undergoing change in its voicing contrast. Whilst speakers vary in both measures, this variability is highly structured: speakers with less aspirated stops are more likely to initiate voicing during the closure. However, no corresponding relationship is observed between how the two cues are used to mark the contrast. These findings extend previous work to demonstrate the structure of speaker variability in spontaneous speech