Reorganization of the auditory-perceptual space across the human vocal range

We investigated the auditory-perceptual space across a substantial portion of the human vocal range (2201046 Hz) using multidimensional scaling analysis of cochlea-scaled spectra from 250-ms vowel segments. Three native German speakers produced vowels /i y e ø ɛ a o u/ (N=240) spanning a wide range of their respective voice frequency ranges, which were subsequently identified in a closed-set task by five phonetically trained listeners (>80% correct response). Our findings revealed systematic spectral alterations associated with vowel height and frontness as fundamental frequency increased and a distinct clustering around /i a u/ above 523 Hz. These results emphasize the importance of the overall spectral shape in vowel perception and demonstrate listeners' utilization of acoustic anchors at higher pitches. Moreover, this study sheds light on the quantal nature of these vowels and their potential impact on language evolution, offering a possible explanation for their widespread presence in the world’s languages.