Quantal Aspects of Consonant Production and Perception: A Study of Retroflex Stop Consonants.

Abstract: The acoustic properties and perceptual characteristics of retroflex stop consonants were explored to determine: (1) if there is an area of acoustic stability which defines the articulatory dimension “retroflexion”; (2) if the range of acoustic characteristics spanning dental to retroflex to velar consonants can be described in terms of discrete properties that are perceived categorically. Acoustic properties of retroflex consonants were determined and were interpreted in terms of acoustic theory. The effectiveness of the various acoustic attributes as cues for identification of retroflex stop consonants was tested by generating CV syllables on a terminal–analog speech synthesizer. The bursts and formant transitions of the syllables were systematically altered to encompass a range of sounds that included dental, retroflex, and velar consonants. The stimuli were presented for identification to eight Hindi-speaking subjects. Three discrete acoustic ranges of stimuli were identified corresponding to the phonetic categories [t ṭ k]: falling F2 and F3 and a high-burst frequency around 4000 Hz for [t]; falling F2, rising F3, and a burst frequency above F3 for [ṭ]; and falling F2, rising F3, and a burst frequency between F2 and F3 for [k]. These results are considered in relation to the quantal theory, auditory property detectors, and theoretical notions of markedness.