Formant modification of sung vowels in four languages

Formant frequencies of sung vowels are modified at higher pitches because of formant tuning, leading to a reduction in intelligibility as the formants converge with increasing F0. Formant frequencies are also dependent on language-specific pronunciation requirements. The question of whether language-specific characteristics of sung vowels are maintained through pitch-effected formant tuning has not previously been examined. Sustained vowels from five similar positions on the vowel quadrilateral in four languages, English, Dutch, French, and Hungarian, were sung in a similar singing style over a range of pitches by a professional female singer who was proficient in singing each of these languages. Formant frequencies were extracted and the magnitudes of the voice partials computed from the average spectrum. The results showed an increase in F1 for the high vowels of all languages, but in the mid–low vowels there were some language differences in the direction of vowel shift as F0 increased. In addition, there were language differences in the relative magnitudes of the partials of all five vowels, particularly at higher frequencies. This suggests that some of the language-specific characteristics of sung vowels may be due to differences in style or voice characteristics.