Vowel dynamics and sentence processing
Diane Kewley-Port, Daniel Fogerty · The Journal of the Acoustical Society of America · 2016
Throughout Terrance Nearey’s influential academic career, research on the acoustic properties, models and theories of vowels has been a major focus. Studies by Nearey and his colleagues demonstrated the importance of spectral change (VISC) in vowel identification, even for monophthongal vowels. This presentation describes our research on vowel dynamics inspired by VISC research. Starting with syllables, the auditory system can discriminate F1 and F2 formants transition differences very well. Further results using high-fidelity resynthesis with sentences revealed that formant discrimination thresholds are 50% smaller than differences observed for natural syllables. These results support that human perception is very sensitive to spectral information in dynamically changing vowels in sentences. A second line of research examined the role of vowel information in sentences using noise interruption paradigms. Based on traditional segment boundaries, vowels had a two-to-one perceptual advantage over consonants for recognizing words in sentences. Shifting boundaries to favor consonantal transitions revealed a large advantage for even small proportions of vowel information. Recent research has enhanced understanding of the interdependence between vowel dynamics and suprasegmental contours of F0 and amplitude for accurate speech recognition. Thus, dynamic information in vowels, both VISC and suprasegmental, is essential for sentence intelligibility.