Avant-garde Dutch 361If it is true that the /͑i/ onset lowering in incipient only in the female part of
the Dutch avant-garde, it makes sense that there should be a greater range of
/͑i/ openness values among the female speakers than among the correspond-
ing group of male speakers. This prediction is clearly borne out by the data in
Figure 15.2. The female scores range between +3.5 Z and –1 Z, whereas the
male scores are roughly between 0 and –1 Z.
- Study 2. Acoustics of Avant-garde /͑͑i/
3.1 Acoustic measurement of vowel quality
Vowel quality, and change of vowel quality in diphthongs, can be quanti¿ ed
by measuring the center frequencies of the lower resonances in the acoustic
signal. Speci¿ cally the center frequency of the lowest resonance of the vocal
tract, called ¿ rst formant frequency or F1, corresponds to the articulatory
and/or perceptual dimension of vowel height. For an average male voice, the
F1 values range between 200 Hertz (Hz) for a high (close) vowel /i/ to some
Figure 15.2 Perceived openness of /͑i/ onset (mean judgments obtained from two
raters, after Z-normalization per rater) for 16 male and 16 female speak-
ers. Individuals are ordered within sexes from left to right in ascending
order of conservatism as determined by their openness score.