Prosodic effects on acoustic cues to stop voicing and place of articulation: Evidence from Radio News speech

This study examines the effects of prosody on the acoustic cues of stop consonants, based on speech from the Boston University Radio News corpus. An investigation of VOT, f0, closure duration, burst amplitude and spectral characteristics provide evidence for a primary effect of accent (a level of phrasal prominence) on these measures as cues to stop voicing and/or place of articulation. There are robust, significant effects of accent on the acoustic cues for both voicing and place of articulation, exhibiting a general pattern of prosodic strengthening. However, the accent effect on voicing cues results in the enhancement of the phonological voice contrast, whereas the effect on acoustic cues to place of articulation does not similarly enhance the place contrast. Comparison of η2 values shows that accent effects are strongest on those measures that are weak cues to the phonological contrast, and weakest on the measures that are strong cues. While there are no observed strengthening effects of phrasal position on voicing cues for /t/ and /d/, acoustic variability is reduced in phrase-initial position.