Acoustic correlate of phonological sonority in British English
Sonority or aperture proposed in linguistic literature can be considered a kind of subjective measure specific to speech perception. Vowels have high sonorities corresponding to a linguistic fact that they can be nuclei of syllables, and fricatives and stops have low sonorities. In order to understand how sonority is perceived, we attempted to find an acoustic dimension on which we could construct a psychophysical scale of sonority. We applied the multivariate analysis method as in Ueda et al. (2010, Fechner Day, Padua) to spoken sentences in British English collected in a commercial database, in which phonemes were segregated and labeled. The speech signals went through a bank of critical-band filters, and the output power fluctuations were subjected to factor analysis. The three factors as in our previous study appeared. The analyzed phonemes were classified into three categories, i.e., vowels, sonorant consonants, and obstruents. These categories were represented well in the Cartesian space whose coordinates were the factor scores of the above factors. One of the factors located around 1000 Hz was highly correlated with sonority or aperture.