Relative duration as a perceptual cue to stress in Mandarin.

Perceptual tests were carried out to examine (1) whether F0 is necessary to perceive stress in Mandarin, and (2) if not, which cue, duration or intensity, is more important. The results indicate that stress can be identified on the basis of duration and intensity alone; duration is a more important cue than intensity. Acoustical analyses of both natural and reiterant speech revealed that both duration and intensity were correlates of stress. There was a ratio of approximately 3:2 between the durations of stressed and unstressed vowels of the same quality, and a difference of nearly 8 dB between their intensities. In addition, segmental changes, such as consonant and vowel reduction, laryngealization, and vowel devoicing, may enhance the perception of the absence of stress.