Timing of pitch movements and perceived vowel duration

The hypothesis was tested that the timing of accent-lending pitch movements influences the perceived duration of a vowel. Dutch subjects were asked to adjust the physical duration of a vowel so as to fit into the temporal structure of a sentence. The vowel occurred in a monosyllabic word embedded in a carrier sentence. Three pitch movements on the vowel were used, a rise, a rise-fall, and a fall. Two opposite trends were found: the earlier the fall, the longer the duration of the target vowel was adjusted, the earlier the rise or rise-fall, the shorter its duration was adjusted. Control experiments indicated that the results should be interpreted in terms of a trade-off between the effects on prominence of timing of pitch movements and physical segment duration. It is concluded that late timing of pitch movements enhances the perceived vowel duration, but that this effect depends on the kind of pitch movement: the effect is cancelled in the case of late rises and rise-falls, whereas it is enhanced in the case of late falls by virtue of the enhancing effect on prominence of the accented syllable

Pitch peak height and focus

The purpose of the present study was to find out how the peak heights of two pitch-accented syllables in one utterance are related to different focus conditions. In a perception experiment, an utterance was presented with various combinations of heights of the first and second pitch peaks. Listeners judged which combination of peak heights best represented one of four focus conditions: neutral focus, double contrastive focus, or single contrastive focus on either the first or second pitch accent. The results showed that the majority of the pitch contours was classified unanimously as signalling only one possible focus condition while only few contours were ambiguous with respect to focus. This knowledge can be used to improve speech synthesis and the automatic interpretation of spoken messages

Perception of prominence in speech intonation induced by rising and falling pitch movements

The object of this study was to investigate whether subjects are able to compare the prominence caused by different types of accent-lending pitch movements and, if so, whether some pitch movements lend more prominence to a syllable than others. These experiments were carried out with the utterance /ma’mama/, with the second syllable accented by either a rise, a fall, or a rise–fall. Subjects adjusted the variable excursion size of a comparison stimulus to the fixed excursion size of a test stimulus in such a way that the accented syllable in test and comparison stimuli had equal prominence. The rise–fall was only presented in one ‘‘standard’’ position, while the fall and the rise were tested for five different temporal positions in the syllable. Subjects were found to be quite capable of equating the prominence of syllables accented by the following types of pitch movement: the rise–fall in standard position, the rise starting before the vowel onset, and the fall whatever its temporal position in the syllable. When lending equal prominence, the early starting rise and the rise–fall had equal excursion sizes. The fall, however, appeared to lend more prominence to a syllable than the rise or the rise–fall of equal excursion size, independent of its position in the syllable. This difference between the fall on the one hand and the rise and the rise–fall on the other increased with increasing declination of the pitch contour. A model is presented which can explain these phenomena quantitatively