Tones in whispered Chinese: articulatory features and perceptual cues
Date
2002
Authors
Gao, Man
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Abstract
Whisper is a common modality of speech communication, regardless of language. In most phonetic studies, descriptions of the larynx during whispering concentrate on the horizontal plane of the glottis. A review of linguistic studies on whispered speech in tone languages shows that there is more concern about people's ability to perceive tones in whispered speech than about how they perceive them, given that the most important perceptual cue, FO, is absent. In order to explain how pitch information is conveyed in the absence of FO, therefore, this study investigates how whispered tones are produced from the perspective of a broader view of the larynx and what contributes to Mandarin Chinese tone recognition in whisper.
Three experiments were conducted in this study. Laryngoscopic endoscopy was used in the first experiment to observe the pharynx and larynx when Mandarin tones are produced in phonated and whispered speech. The second experiment involved data collection for acoustic analysis. Two male and two female native speakers of Mandarin produced three sets of syllables with four contrasting tones in isolation and in sentential environments. The data collected were analyzed acoustically with speech-analysis software and played as stimuli to ten native speakers of Mandarin in the third experiment, a perception test.
A number of conclusions were drawn based on the results of these experiments: (1) the laryngeal sphincter mechanism is found to be a principal contributing physiological maneuver in the production of whisper, emphasizing the vertical rather than the horizontal component of the laryngeal source; (2) two special behavioral maneuvers are also used in whisper: male speakers tend to lengthen vocalic duration and female speakers tend to exaggerate the amplitude contours of Tone 3 and Tone 4; (3) these two special behavioral maneuvers and two temporal envelope parameters contribute to tone recognition in whisper, but the phonetic context is shown to be a distraction; (4) the environments of the target tones cause perceptual differences, and the ranking of these environments in order of increasing degree of difficulty is: isolation, sentence-final, sentence-medial and sentence-initial; (5) the ranking of the four tones in isolation, in order of increasing degree of perceptual difficulty is: Tone 3, Tone 4, Tone l and Tone 2.
This is the first time that empirical evidence has been gathered to test the notion of 'special maneuver' proposed by linguists in the 1970s; it is also a first look in depth at the articulatory production mechanism for whisper. This study contributes to our knowledge of the phonetic production and linguistic realization of whispered tones in Mandarin Chinese by providing a complete description of the articulatory mechanism and a comprehensive report on how they are perceived in various environments.