Acoustic comparison of /t/ glottalization and phrasal creak
Marc Garellek, Scott Seyfarth · The Journal of the Acoustical Society of America · 2016
In American English, the presence of creaky voice can derive from distinct linguistic processes, including phrasal creak (prolonged irregular voicing, often at edges of prosodic phrases) and coda /t/ glottalization (when the alveolar closure for syllable-final /t/ is replaced by or produced simultaneously with glottal constriction). Garellek (2015) showed that listeners can differentiate words in phrasal creak from those with /t/ glottalization, which suggests that the creaky voice derived from phrasal creak and /t/ glottalization differ acoustically. To test this, we analyzed vowels preceding syllable-final /t/ in the Buckeye Corpus, which is comprised of audio recordings of spontaneous speech from 40 speakers of American English. Tokens were coded for presence of phrasal creak (prolonged irregular voicing extending beyond the target syllable) and /t/ glottalization (whether the /t/ was produced only with glottal constriction). Spectral measures of voice quality, including both harmonic and noise measures, were extracted automatically using VoiceSauce (Shue et al., 2011), and discriminant analyses were performed. The results indicate several differences among non-creaky vowels, vowels before glottalized /t/, and vowels in phrasal creak. The discussion will focus on how different sub-categories of creaky voice can contrast with one another in a given language.