Associations Between Speaking Fundamental Frequency, Vowel Formant Frequencies, and Listener Perceptions of Speaker Gender and Vocal Femininity-Masculinity

The Effectiveness of Gender Affirming Voice Training for Transfeminine Clients: A Comparison of Traditional Versus Intensive Delivery Schedules

INTRODUCTION

Gender affirming voice training is a service provided by speech language pathologists to members of the trans and gender diverse community. While there is some evidence to support the effectiveness of this training, the evidence base is limited by a lack of prospective studies with large sample sizes. Finally, there has been only limited research investigating the effectiveness of this training when delivered on intensive (compressed) schedules, even though such schedules are used in clinical practice and may have practical benefits such as increasing service access for this vulnerable population.

METHODOLOGY

This study aimed to investigate and compare the effectiveness gender affirming voice training among 34 trans individuals presumed male at birth aiming to develop a perceptually feminine/female-sounding voice. Among these 34 participants, 17 received their training on a traditional schedule (one 45-minute session per week over 12 weeks) and 17 on an intensive scheduled (three 45-minute sessions per week over 4 weeks). Building on a previous mixed methodological study which indicated that these two training groups were equally satisfied with training outcomes, the current study utilised a wide range of self-report, acoustic, and auditory-perceptual outcome measures (including self-ratings and listener-ratings of voice) to investigate training effectiveness.

DISCUSSION

Results from this study indicated that both training programs were similarly effective, producing positive statistically significant change among participants on a range of outcome measures. Participants in both groups demonstrated significant auditory-perceptual and acoustic voice change and reported increased satisfaction with voice, increased congruence between gender identity and expression, and a reduction in the negative impact of voice concerns on everyday life. However, as has been the case in past studies, training was not sufficient for all participants to achieve their goal of developing a consistently feminine/female-sounding voice.

CONCLUSION

This study provides evidence to suggest that gender affirming voice training for transfeminine clients may be similarly effective whether delivered intensively or traditionally. This study provides evidence to support the practice of using a wide range of outcome measures to gain holistic insight into client progress in gender affirming voice training programs.

Perception of Femininity and Masculinity in Voices as Rated by Transgender and Gender Diverse People, Professional Speech and Language Pathologists, and Cisgender Naive Listeners

OBJECTIVE

To explore whether cisgender naive listeners, transgender and gender diverse (TGD) listeners, and speech-language pathologists (SLPs) experienced in providing gender-affirming voice training differ in their perception of femininity and masculinity in voices.

METHODS

Samples of spontaneous speech were collected from 95 cisgender, and 37 TGD speakers. Three listener groups of cisgender naive (N = 77), TGD (N = 30), and SLP (N = 14) listeners, respectively, rated the voices on visual analog scales in two randomly ordered blocks, in which the perceived degree of femininity was rated separately from the perceived degree of masculinity.

RESULTS

The three listener groups showed similar patterns in their distribution of ratings on the femininity and masculinity scales. The TGD listeners' mean ratings did not differ from the cisgender naive listeners', whereas SLPs showed a small, but significant, difference in their ratings compared with both TGD and cisgender naive listeners and rated the voices lower on both the femininity and masculinity scales.

CONCLUSION

The results differ from previous studies as TGD, and cisgender naive listeners rated the voices very similarly. The lower ratings of femininity and masculinity by the SLPs were likely influenced by their awareness of the complexity in the perception of voices. Therefore, SLPs providing gender-affirming voice training should be attentive to how their professional training may influence their perception of femininity and masculinity in voices and encourage discussions and explorations of the TGD voice client's perceptions of voices.

Long-term Acoustic Effects of Gender-Affirming Voice Training in Transgender Women

OBJECTIVES

One role of a speech-language pathologist (SLP) is to help transgender clients in developing a healthy, gender-congruent communication. Transgender women frequently approach SLPs to train their voices to sound more feminine, however, long-term acoustic effects of the training needs to be rigorously examined in effectiveness studies. The aim of this study was to investigate the long-term effects (follow-up 1: 3months and follow-up 2: 1year after last session) of gender-affirming voice training for transgender women, in terms of acoustic parameters.

STUDY DESIGN

This study was a randomized sham-controlled trial with a cross-over design.

METHODS

Twenty-six transgender women were included for follow-up 1 and 18 for follow-up 2. All participants received 14weeks of gender-affirming voice training (4weeks sham training, 10weeks of voice feminization training: 5weeks pitch elevation training and 5weeks articulation-resonance training), but in a different order. Speech samples were recorded with Praat at four different time points (pre, post, follow-up 1, follow-up 2). Acoustic analysis included fo of sustained vowel /a:/, reading and spontaneous speech. Formant frequencies (F1-F2-F3) of vowels /a/, /i/, and /u/ were determined and vowel space was calculated. A linear mixed model was used to compare the acoustic voice measurements between measurements (pre - post, pre - follow-up 1, pre - follow-up 2, post - follow-up 1, post - follow-up 2, follow-up 1 - follow-up 2).

RESULTS

Most of the fo measurements and formant frequencies that increased immediately after the intervention, were stable at both follow-up measurements. The median fo during the sustained vowel, reading and spontaneous speech stayed increased at both follow-ups compared to the pre-measurement. However, a decrease of 16 Hz/1.7 ST (reading) and 12 Hz/1.5 ST (spontaneous speech) was detected between the post-measurement (169 Hz for reading, 144 Hz for spontaneous speech) and 1year after the last session (153 Hz and 132 Hz, respectively). The lower limit of fo did not change during reading and spontaneous speech, both directly after the intervention and during both follow-ups. F1-2 of vowel /a/ and the vowel space increased after the intervention and both follow-ups. Individual analyses showed that more aspects should be controlled after the intervention, such as exercises that were performed at home, or the duration of extra gender-affirming voice training sessions.

CONCLUSIONS

After 10 sessions of voice feminization training and follow-up measurements after 3months and 1year, stable increases were found for some formant frequencies and fo measurements, but not all of them. More time should be spent on increasing the fifth percentile of fo, as the lower limit of fo also contributes to the perception of more feminine voice.

Acoustic cues to femininity and masculinity in spontaneous speech

The perceived level of femininity and masculinity is a prominent property by which a speaker's voice is indexed, and a vocal expression incongruent with the speaker's gender identity can greatly contribute to gender dysphoria. Our understanding of the acoustic cues to the levels of masculinity and femininity perceived by listeners in voices is not well developed, and an increased understanding of them would benefit communication of therapy goals and evaluation in gender-affirming voice training. We developed a voice bank with 132 voices with a range of levels of femininity and masculinity expressed in the voice, as rated by 121 listeners in independent, individually randomized perceptual evaluations. Acoustic models were developed from measures identified as markers of femininity or masculinity in the literature using penalized regression and tenfold cross-validation procedures. The 223 most important acoustic cues explained 89% and 87% of the variance in the perceived level of femininity and masculinity in the evaluation set, respectively. The median fo was confirmed to provide the primary cue, but other acoustic properties must be considered in accurate models of femininity and masculinity perception. The developed models are proposed to afford communication and evaluation of gender-affirming voice training goals and improve voice synthesis efforts.

Gender-Affirming Voice Training for Trans Women: Acoustic Outcomes and Their Associations With Listener Perceptions Related to Gender

OBJECTIVES

To investigate acoustic outcomes of gender-affirming voice training for trans women wanting to develop a female sounding voice and to describe what happens acoustically when male sounding voices become more female sounding.

STUDY DESIGN

Prospective treatment study with repeated measures.

METHODS

N = 74 trans women completed a voice training program of 8-12 sessions and had their voices audio recorded twice before and twice after training. Reference data were obtained from N = 40 cisgender speakers. Fundamental frequency (fo), formant frequencies (F1-F4), sound pressure level (Leq), and level difference between first and second harmonic (L1-L2) were extracted from a reading passage and spontaneous speech. N = 79 naive listeners provided gender-related ratings of participants' audio recordings. A linear mixed-effects model was used to estimate average training effects. Individual level analyses determined how changes in acoustic data were related to listeners' ratings.

RESULTS

Group data showed substantial training effects on fo (average, minimum, and maximum) and formant frequencies. Individual data demonstrated that many participants also increased Leq and some increased L1-L2. Measures that most strongly predicted listener ratings of a female sounding voice were: fo, average formant frequency, and Leq.

CONCLUSIONS

This is the largest prospective study reporting on acoustic outcomes of gender-affirming voice training for trans women. We confirm findings from previous smaller scale studies by demonstrating that listener perceptions of male and female sounding voices are related to acoustic voice features, and that voice training for trans women wanting to sound female is associated with desirable acoustic changes, indicating training effectiveness. Although acoustic measures can be a valuable indicator of training effectiveness, particularly from the perspective of clinicians and researchers, we contend that a combination of outcome measures, including client perspectives, are needed to provide comprehensive evaluation of gender-affirming voice training that is relevant for all stakeholders.

Gender Attributions by Cisgender and Gender Diverse Listeners Rating Vowels, Reading, and Monologues

OBJECTIVES

To determine if listeners' attributions of speakers' gender vary by linguistic context and/or the listeners' gender identity.

METHODS

Seventeen self-identified transgender adults assigned male at birth were audio-recorded prolonging /a/, reading sentences, and saying spontaneous monologues. Eighteen adults (10 cisgender and 8 gender-diverse individuals) listened and used a 1-5 scale (1: very masculine, 2: somewhat masculine, 3: androgynous, 4: somewhat feminine, and 5: very feminine) to rate the gender attribution of each speech sample.

RESULTS

The intra-rater reliability was moderate to excellent (0.62-1.00). Ratings by cisgender and gender-diverse listeners were not significantly different. Ratings were not significantly different between different speech contexts of vowel, reading, and spontaneous monologue speech samples.

CONCLUSIONS

Transwomen have many variables available to consider and use in their communication. The linguistic context (eg, reading a speech versus spontaneous monologue) or listener's gender does not appear to be highly influential factors in how listeners attribute gender.

Gender-Affirming Voice Training for Trans Women: Effectiveness of Training on Patient-Reported Outcomes and Listener Perceptions of Voice

PURPOSE

Although speech-language pathologists have provided gender-affirming voice training for trans women since the 1970s, evidence for this training's effectiveness remains weak. Our study aimed to redress limitations of earlier studies and evaluate voice training effects on outcomes important to trans women.

METHOD

Seventy-four trans women (19-54 years old) who wanted a more female-sounding voice were recruited through two health facilities and provided with an eight- to 12-session voice training program based on contemporary literature, usual clinical practice, and client-centered care principles. Self-reported outcomes and an audio-recorded reading sample were collected 3 months before, immediately before and after, and 3 months after training. Forty cisgender speakers were audio-recorded reading the same sample material as comparison voices. Seventy-nine naive listeners made gender-related voice ratings of an extract from these audio recordings. Training effectiveness was evaluated using group-level analyses (linear mixed-effects models) and individual-level analyses to establish what proportion of participants improved to a predetermined relevant degree.

RESULTS

Group-level analyses demonstrated positive training effects, maintained 3 months posttraining, for trans women's vocal satisfaction, perceptions of voice-related social participation, and self- and listener perceptions of their voices. Individual-level analyses also demonstrated positive effects. Two thirds of trans women increased vocal satisfaction to a relevant degree, one third who reported restricted social participation before training reduced this restriction to a relevant degree, and all were rated more female-sounding after training (although not all to a relevant degree).

CONCLUSIONS

All trans women participants made progress toward their voice goals and maintained those gains at follow-up. These findings provide evidence that gender-affirming speech-language pathology services warrant prioritization. Further research is warranted to investigate factors predicting outcomes of voice training for trans women.

Short-term effects of a speech feminization program for transgender women: listener perceptions, self-perception and satisfaction of the voice

Purpose: This study measured and compared the short-term impact of pitch elevation training (PET) and articulation-resonance training (ART) in transgender women, on self-perception, satisfaction and masculinity-femininity perceptions of listeners. Methods: A randomized controlled study with cross-over design was used. Thirty transgender women were included and received fourteen weeks of speech training. All participants started with sham training (four weeks), after which they were randomly assigned to one of two groups: one group continued with PET (five weeks), followed by ART (five weeks), the second group received both trainings in opposite order. Participants were recorded four times, in between the training blocks: pre, post 1 (after sham), post 2 (after training 1) and post 3 (after training 2). Participants did a self-evaluation through the Trans Woman Voice Questionnaire (TWVQ) and visual analogues scales (VAS) concerning their self-perception and satisfaction. Two listening experiments (n = 75) were conducted researching the continuous masculinity-femininity rating (through a VAS) and categorical masculinity-femininity attribution. Results and conclusions: Transgender women perceive their voices more feminine after the training and experience a positive impact on the vocal functioning and the voice-related impact on their daily life. However, a lot of the participants acknowledge that they need more speech training after ten weeks. Listeners rate the participants' voices more feminine after training, both during the continuous and categorical questions. Higher femininity scores were detected during self-perception and listener perceptions after the combination of both ART and PET, compared to the separate trainings. No order effects were detected between ART and PET, both for self-perception and listener perceptions. Defining outcome predictors is crucial in future research.

Speech beyond the binary: Some acoustic-phonetic and auditory-perceptual characteristics of non-binary speakers

Speech acoustics research typically assumes speakers are men or women with speech characteristics associated with these two gender categories. Less work has assessed acoustic-phonetic characteristics of non-binary speakers. This study examined acoustic-phonetic features across adult cisgender (15 men and 15 women) and subgroups of transgender (15 non-binary, 7 transgender men, and 7 transgender women) speakers and relations among these features and perceptual ratings of gender identity and masculinity/femininity. Differing acoustic-phonetic features were predictive of confidence in speaker gender and masculinity/femininity across cisgender and transgender speakers. Non-binary speakers were perceptually rated within an intermediate range of cisgender women and all other groups.

Short-Term Acoustic Effects of Speech Therapy in Transgender Women: A Randomized Controlled Trial

PURPOSE

This study measured and compared the acoustic short-term effects of pitch elevation training (PET) and articulation-resonance training (ART) and the combination of both programs, in transgender women.

METHOD

A randomized controlled study with cross-over design was used. Thirty transgender women were included and received 14 weeks of speech training. All participants started with 4 weeks of sham training; after which they were randomly assigned to one of two groups: One group continued with PET (5 weeks), followed by ART (5 weeks); the second group received both trainings in opposite order. Participants were recorded 4 times, in between the training blocks: pre, post 1 (after sham), post 2 (after training 1), and post 3 (after training 2). Speech samples included a sustained vowel, continuous speech during reading, and spontaneous speech and were analyzed using Praat software. Fundamental frequency (f _o), intensity, voice range profile, vowel formant frequencies (F _1-2-3-4-5 of /a/-/i/-/u/), formant contrasts, vowel space, and vocal quality (Acoustic Voice Quality Index) were determined.

RESULTS AND CONCLUSIONS

Fundamental frequencies increased after both the PET and ART program, with a higher increase after PET. The combination of both interventions showed a mean increase of the f _o of 49 Hz during a sustained vowel, 49 Hz during reading, and 29 Hz during spontaneous speech. However, the lower limit (percentile 5) of the f _o during spontaneous speech did not change. Higher values were detected for F _1-2 of /a/, F ₃ of /u/, and vowel space after PET and ART separately. F _1-2-3 of /a/, F _1-3-4 of /u/, vowel space, and formant contrasts increased after the combination of PET and ART; hence, the combination induced more increases in formant frequencies. Intensity and voice quality measurements did not change. No order effect was detected; that is, starting with PET or ART did not change the outcome.

The Effects of Pitch Manipulation on Male Ratings of Female Speakers and Their Voices

Vocal and facial cues typically co-occur in natural settings, and multisensory processing of voice and face relies on their synchronous presentation. Psychological research has examined various facial and vocal cues to attractiveness as well as to judgements of sexual dimorphism, health, and age. However, few studies have investigated the interaction of vocal and facial cues in attractiveness judgments under naturalistic conditions using dynamic, ecologically valid stimuli. Here, we used short videos or audio tracks of females speaking full sentences and used a manipulation of voice pitch to investigate cross-modal interactions of voice pitch on facial attractiveness and related ratings. Male participants had to rate attractiveness, femininity, age, and health of synchronized audio-video recordings or voices only, with either original or modified voice pitch. We expected audio stimuli with increased voice pitch to be rated as more attractive, more feminine, healthier, and younger. If auditory judgements cross-modally influence judgements of facial attributes, we additionally expected the voice pitch manipulation to affect ratings of audiovisual stimulus material. We tested 106 male participants in a within-subject design in two sessions. Analyses revealed that voice recordings with increased voice pitch were perceived to be more feminine and younger, but not more attractive or healthier. When coupled with video recordings, increased pitch lowered perceived age of faces, but did not significantly influence perceived attractiveness, femininity, or health. Our results suggest that our manipulation of voice pitch has a measurable impact on judgements of femininity and age, but does not measurably influence vocal and facial attractiveness in naturalistic conditions.

Voice and Speech Changes in Transmasculine Individuals Following Circumlaryngeal Massage and Laryngeal Reposturing

PURPOSE

The purpose of this study was to measure the short-term effects of circumlaryngeal massage and laryngeal reposturing on acoustic and perceptual characteristics of voice in transmasculine individuals.

METHOD

Fifteen transmasculine individuals underwent one session of sequential circumlaryngeal massage and laryngeal reposturing with a speech-language pathologist. Voice recordings were collected at three time points-baseline, postmassage, and postreposturing. Fundamental frequency (f o), formant frequencies, and relative fundamental frequency (RFF; an acoustic correlate of laryngeal tension) were measured. Estimates of vocal tract length (VTL) were derived from formant frequencies. Twelve listeners rated the perceived masculinity of participants' voices at each time point. Repeated-measures analyses of variance measured the effect of time point on f o, estimated VTL, RFF, and perceived voice masculinity. Significant effects were evaluated with post hoc Tukey's tests.

RESULTS

Between baseline and end of the session, f o decreased, VTL increased, and participant voices were perceived as more masculine, all with statistically significant differences. RFF did not differ significantly at any time point. Outcomes were highly variable at the individual level.

CONCLUSION

Circumlaryngeal massage and laryngeal reposturing have short-term effects on select acoustic (f o, estimated VTL) and perceptual characteristics (listener-assigned voice masculinity) of voice in transmasculine individuals.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.19529299.