Acoustic Features of Transfeminine Voices and Perceptions of Voice Femininity

The purpose of this study was to evaluate the relationships between acoustic measures of transfeminine voices and both self- and listener ratings of voice femininity. Connected speech samples were collected from 12 transfeminine individuals (M = 36.3 years, SD = 10.6 years) and a control group of five cisgender (cis) women and five cis men (M = 35.3 years, SD = 13.3 years). The acoustic measures of fundamental frequency (f_o), f_o variation, formant frequencies, and vocal intensity were calculated from these samples. Transfeminine speakers rated their own voices on a five-point scale of voice femininity. Twenty inexperienced listeners heard an excerpt of each speech sample and rated the voices on the same five-point scale of voice femininity. Spearman's rank-order correlation coefficients were calculated to measure the relationships between the acoustic variables and ratings of voice femininity. Significant positive correlations were found between f_o and both self-ratings (r = 0.712, P = 0.009) and listener ratings of voice femininity (r = 0.513, P < 0.001). Significant positive correlations were found between intensity and both self-ratings (r = 0.584, P = 0.046) and listener ratings of voice femininity (r = 0.584, P = 0.046). No significant correlations were found between f_o variation or formant frequencies and perceptual ratings of voice femininity. A Pearson's chi-square test of independence showed that the distribution of self- and listener ratings differed significantly (χ² = 9.668, P = 0.046). Self- and listener ratings were also shown to be strongly correlated (r = 0.912, P < 0.001). This study provides further evidence to support the selection of training targets in voice feminization programs for transfeminine individuals and promotes the use of self-ratings of voice as an important outcome measure.