Vowel intrinsic pitch influences the perception of intonational prominence

Abstract

The relative prominence of accented syllables in a sentence depends on the relative heights of the associated F0 peaks in the intonation contour. An experiment was conducted to investigate whether it also depends on the associated vowel quality. /i:/ and /a:/ vowels were spliced into frame sentences to yield pairs such as “We peeked before parking” / “We parked before peeking,” with intonational peaks in both accented syllables. Versions were resynthesized with the F0 height in the second accent varied from higher than to lower than that in the first. Listeners judged which of the two accented syllables sounded more prominent. Results suggest that F0 must be higher in /i:/ than in /a:/ for the two to sound equally prominent. By implication, a single F0 contour can convey different intonational structures if just the vowel quality varies. This implies that the mapping from F0 to linguistic prominence includes compensatory adjustment for vowel intrinsic pitch. Consequently, during speech synthesis, vowel intrinsic pitch should be included in the calculation of F0 contours to ensure accurate listener reconstruction of prosodic structure.