Weighting of Coda Voicing Cues: Glottalisation and Vowel Duration

Recent research suggests that a trading relationship may exist in speech production between vowel duration and glottalisation as cues to coda stop voicing in Australian English. Younger speakers have been shown to use glottalisation to signal voicelessness more than older speakers who instead make greater use of vowel duration. This suggests a sound change in progress for the voicing cues. In addition, the vowel duration cue to voicing is greater in inherently long vowel contexts compared to inherently short vowel contexts. We report on a perceptual study designed to examine whether the weighting of these two cues found in production is replicated in perception. Older and younger listeners were presented with audio stimuli co-varying in vowel duration and glottalisation. In accord with findings from production, the vowel duration cue was weaker for contexts containing inherently short vowels than for those containing inherently long vowels. Complementarily, glottalisation had a stronger effect on the perception of coda voicelessness in inherently short vowel contexts. Older and younger listeners did not differ in their use of glottalisation as a perceptual cue to voicelessness despite previously identified age differences in production. This finding raises questions about the link between perception and production in sound change.