The purpose of this dissertation is threefold: i) to determine the number and acoustic-motor characteristics of the different phonation types, ii) to develop auditorily-based speech processing methods suitable for the measurement of glottal parameters, iii) to provide two equipollent pairs of glottal manner features that categorize the phonation types into the appropriate natural classes.
Nine pitch-independent phonation types appear necessary to account for linguistically significant contrasts: 1) glottal stop, 2) whisper, 3) breath, 4) harsh voice, 5) harsh whispery voice, 6) breathy voice, 7) tense voice, 8) plain voice, 9) lax voice. The phonation types (1, 2, 3) form the category of glottal noise while (2, 3) constitute voicelessness. The phonation types (4, 5, 6) are categorized as noisy voice, the phonation types (7, 8, 9) as pure voice. The three glottal noise phonation types (1, 2, 3) are characterized by aperiodic waveforms and exhibit increasingly larger glottal openings from 1) glottal stop to 3) breath. Because acoustic damping grows with widening glottal aperture, the first formant bandwidth (B1) likewise broadens. The three noisy voice phonation types (4, 5, 6) are characterized by periodic waveforms and have either considerable modulation noise (harsh voice), aspiration noise (breathy voice), or both (harsh whispery voice). The three pure voice phonation types (7, 8, 9) are also characterized by periodic waveforms, but with no significant modulation or aspiration noise, tense voice being cued by a flat spectral tilt, plain
voice by an intermediate spectral tilt, lax voice by a steep spectral tilt.
The nine phonation types are classified both by I. a three-by-three motor hierarchy and II. a linear acoustic scale of derived glottal bandwidth (GBW) that progressively narrows from 1) glottal stop to 9) lax voice. The primary motor features of position consist of the antagonistic pair [voice, noise]. The secondary motor features of stricture consist of the antagonistic pair [constricted, spread]. To demonstrate the generality of the feature framework adopted for glottal manner, equipollent feature systems for vowel height, backness, and supraglottal manner (major class features) are also proposed.
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