Intelligibility and spectral differences in high-pitched vowels.

The first formant frequency of most German vowels can be 'oversung' in the sense of vocalizations with pitch frequencies above F1 of normal speech. Investigations of sung and synthesized vowels suggested that, with rising F0, either the vowel loses its identity and its spectral characteristics, or changes in the vocal effort and the speaker group are perceived. This study presents high-pitched vocalizations by untrained men, women and children, apart from singing or shouting. Three main results were found: (i) vowel identity can be maintained at high pitches (F0 = 660-870 Hz); (ii) clear spectral differences in high-pitched vowels are demonstrated; (iii) high pitched vowels can be found within one speaker group, apart from changes in the perceived speaker group. Both the F0 dependence of the lower formants and a possible relationship between phonation and articulation are discussed.