Trans Voice Literature Review №3

I perused some more academic databases and found a bunch articles that didn't surface in my earlier research; One is from this year!

8. Oates, J., Södersten, M., Quinn, S., Nygren, U., Dacakis, G., Kelly, V., Smith, G., & Sand, A. (2023). Gender-Affirming Voice Training for Trans Women: Effectiveness of Training on Patient-Reported Outcomes and Listener Perceptions of Voice. Journal of Speech, Language & Hearing Research, 66(11), 4206–4235. https://doi.org/10.1044/2023_JSLHR-23-00258

   TL;DR: Eight to 12 training sessions (at one session per week) with 74 participants. A variety of techniques and approaches were used during training. Non-SLP raters were used, who rated three months before, immediately before, immediately after, and three months after. Following training, 20 participants were rated as "somewhat female" to "very female" and maintained, 3 participants were rated as "somewhat female" and degraded to "gender neutral", and the remaining 51 saw minor improvement from their starting point (anywhere in the range from "very male" to "somewhat female").

   Methodology: The techniques and approahces used were lip spreading, forward tongue carriage, SOVT (resonance tube, straw phonation, lip/tongue trills, "accent method", VFE, resonant voice training, perceptual-motor learning principles, visual biofeedback, clinician modeling, negative/positive practice. Participants were instructed to target 220Hz from the very start of the training (or as close as possible to that pitch without strain/hyperfunction). Then intonational pitch variation based on the 220Hz anchor. Apps participants were recommended to use during home practice include Voice Pitch Analyzer, Vocal Pitch Monitor, Voice Tools, and Voice Analyst: Pitch and Volume.

   Discussion: "It is also possible that some of our participants were simply not finished with their voice training. Some might have achieved our threshold for relevant change with additional sessions," (p. 4227). Results may also have been affected by the onset of the pandemic.

   Review: The exclusion of SLPs from the rater group helps alleviate the issues raised by Holmberg et al. [7]. However, the authors report that the naive raters reported the task as challenging and that "they were less sure of their judgements if they did not immediately perceive the speaker as 'definitely a man or a woman' (p. 4226). The methodology did not define in detail the voice training techniques used, but they did cite other papers which may be helpful to review. We're seeing a weird half distribution of outcomes here, with 23/74 ending up feminine fter the training. Is it simply lack of time like the authors suggest, or is there some other factor causing this?

   1. Verdolini Abbott, K. (2008). Lessac–Madsen resonant voice therapy: Clinician manual. Plural.

   2. Thyme, K., & Frøkjær-Jensen, B. (2001). The accent method: A rational voice therapy in theory & practice. Speechmark.

   3. Angadi, V., Croake, D., & Stemple, J. (2019). Effects of vocal function exercises: A systematic review. Journal of Voice, 33(1), 124.e13–124.e34. https://doi.org/10.1016/j.jvoice.2017.08.031

      TL;DR: Lit review looked at 21 studies to determine efficacy of VFE. Did not go into detail about how VFE works or procedures.

   4. Stemple, J. C., Lee, L., D’Amico, B., & Pickup, B. (1994). Efficacy of vocal function exercises as a method of improving voice production. Journal of Voice, 8(3), 271–278. https://doi.org/10.1016/s0892-1997(05)80299-1

9. Papeleu, T., Oates, J., Tomassen, P., Adriaansen, A., Leyns, C., Alighieri, C., Krenn, H., & D’haeseleer, E. (2025). Effects of Intensive Intonation Training in Transgender and Gender Diverse People Aiming for a More Feminine-Sounding Voice: A Randomized Clinical Trial. Journal of Speech, Language & Hearing Research, 68(4), 1711–1742. https://doi.org/10.1044/2024_JSLHR-24-00563

   TL;DR: Four weeks of intonation training with 30 participants (one hour of training per week). Raters rated participants as mostly gender neutral both immediately after training and after 4 weeks.

   Background: "SFF is the most studied parameter but only contributes to 41.6% of the variance in gender perception," "Merritt and Bent (2022) found that changes in F0 and resonance characteristics are insufficient to effectively alter preceived speaker gender," (p. 1712). "The aim of the intonation training for TGD people who desired for a more feminine-sounding voice was to achieve fewer extensive downward intonation patterns, and a larger F0 range," (p. 1713).

   Voice Training Protocol (Appendix A): Apps recommended for at-home study were Intonia, Vocal Friend, and Voice Tools. Sessions as numbered:

   1. Pitch biofeedback, auditory discrimination with voice samples, warm up exercises varying between high and low tones, counting up from 1 to 10 from old pitch to a higher pitch, then old pitch to higher pitch for vowels, syllables, and words.
   2. Recap of prior session, speaking with more pitch variation, making sure there are a lot of upward intonation patterns - questions and short sentences, speaking with fewer downward intonation patterns, especially at the end of an utterance, poems, texts and semispontaneous speech.
   3. Recap of prior session, speaking with more pitch variation - long texts, recipes, describing pictures.
   4. Recap of prior session, role playing job applications, telephone conversations.

   Review: Just like many other studies, this one falls short of getting the participants into the feminine voice rating range. But it is interesting to see how much they were able to accomplish with so limited a scope. Just intonation!

   1. Merritt, B., & Bent, T. (2022). Revisiting the acoustics of speaker gender perception: A gender expansive perspective. The Journal of the Acoustical Society of America, 151(1), 484–499. https://doi.org/10.1121/10.0009282

      TL;DR: Listeners rated 24 speakers (12 cis [6 female, 6 male], 12 trans [6 transfem, 6 transmasc]). Altering F0 of recordings and using the "change gender" function in Praat (formant alteration) were not enough to alter all gender judgements. Articulatory cues had a greater weighting than intonation cues when f0 and formant frequencies were in a gender ambiguous range.

      Review: This is fascinating. It goes against most of the previous articles we've looked at, but it kind of makes sense! Most of the studies struggle to get participants into the ambiguous range when looking at F0 or F2 in isolation, with a bit better success for both. This study claims that F0 and F2 are only a part of the puzzle, and that articulatory cues were most important for getting through the ambiguous range (though intonation could help too).

10. Loutrari, A., & Georgiadou, I. (2024). Adapted melodic intonation therapy can help raise trans women’s singing and speaking fundamental frequencies. Logopedics Phoniatrics Vocology, 49(2), 58–65. https://doi.org/10.1080/14015439.2022.2121985

    TL;DR: two one-to-one sessions four weeks apart with 11 participants (daily home exercises during the gap). Nine out of 11 participants had an F0 over 175Hz following training. Voices were not rated for femininity.

    Background: Gelfer and Van Dong (2013) implementation of VFE: holding the vowel /i/ at 262Hz, gliding from one's lowest to their heighest note and vice versa and holding five successive notes starting at 196Hz while articulating /ɒ/.

    Review: The lack of ratings makes it difficult to assess the efficacy of the study. It theoretically hits on both F0 and intonation, which should make it at least somewhat viable, but without confirmation.

11. Merrick, G., Figol, A., Anderson, J., & Lin, R. J. (2022). Outcomes of Gender Affirming Voice Training: A Comparison of Hybrid and Individual Training Modules. Journal of Speech, Language, and Hearing Researc : JSLHR, 65(2), 501–507. https://doi.org/10.1044/2021_JSLHR-21-00056

    TL;DR: 62 participants attended either individual or hybrid training. Both routes saw F0 increases (135Hz to 161Hz hybrid, 131Hz to 175Hz individual). No voice rating was done.

    Review: The main goal of the study seems to be to display the effectiveness of hybrid training, which if you consider the reduced SLP workload is admirable, but the F0 increase was better for individual training. Either way, F0 is only a small part of voice training.

12. Bush, E. J., Krueger, B. I., Cody, M., Clapp, J. D., & Novak, V. D. (2024). Considerations for Voice and Communication Training Software for Transgender and Nonbinary People. Journal of Voice : Official Journal of the Voice Foundation, 38(5), 1251.e1-1251.e20. https://doi.org/10.1016/j.jvoice.2022.03.002

    TL;DR: A survey sent out to participants asking them for feedback on VCT apps. The four apps listed in the survey were EvaF.app, Christella VoiceUp, Project Spectra, and Voice Pitch Analyzer.

13. Quinn, S., Oates, J., & Dacakis, G. (2024). The Effectiveness of Gender Affirming Voice Training for Transfeminine Clients: A Comparison of Traditional Versus Intensive Delivery Schedules. Journal of Voice : Official Journal of the Voice Foundation, 38(5), 1250.e25-1250.e52. https://doi.org/10.1016/j.jvoice.2022.03.001

    TL;DR: 34 participants attended either traditional or intensive training sessions. The traditional sessions took place over 12 weeks at one session per week, while the intensive sessions took place over four weeks at three sessions per week. Outcomes were approximately equivalent, ending up in the androgynous range by rating without degredation three months later. Formant analysis was not feasible due to the way in which data was collected.

    Background: F0 mean and F0 range were selected gender signifiers; the authors used >180Hz for F0 mean and a minimum/trough F0 of >140Hz to indicate femininity.

    Methodology: exercises to maximize breath support and engage diaphragmatic breathing, head neck and trunk stretches, vocal warm ups and SOVT exercises, VFE (Vocal Function Exercises), and resonant voice exercises. Daily at-home practice recommended.

    Discussion: Previous studies expressed concern that intensive voice training could lead to vocal overuse and negative changes, while this study indicates that might not be the case.

    Review: Much as stated in the discussion, this study raises questions about whether vocal overuse is a concern for trans voice training. Unfortunately, as with most studies, the participants ended up in the androgynous zone. This is a recurring problem, but shows at least that the speed at which this style of training is done has little effect on the efficacy.

14. Hardy, T. L. D., Boliek, C. A., Wells, K., Dearden, C., Zalmanowitz, C., & Rieger, J. M. (2016). Pretreatment Acoustic Predictors of Gender, Femininity, and Naturalness Ratings in Individuals With Male-to-Female Gender Identity. American Journal of Speech-Language Pathology, 25(2), 125–137. https://doi.org/10.1044/2015_AJSLP-14-0098

    TL;DR: 25 speakers, 30 listeners/raters. Trans women who have not voice trained are typically rated as vocally male. Voice naturalness was most likely derived from F0 trough (lowest/minimum F0), F2, and shimmer percentage (related to vocal hoarseness).

15. Hancock, A. B., Stutts, H. W., & Bass, A. (2015). Perceptions of Gender and Femininity Based on Language: Implications for Transgender Communication Therapy. Language & Speech, 58(3), 315–333. https://doi.org/10.1177/0023830914549084

    TL;DR: Identifying gender by language use is at best near chance. (Ex: negation, progressive verbs, justifiers, hedges, intensive adverb, filler, self-reference, etc.). "The lack of measured and perceptible differences calls into question the utility of training key language features in transgender communication therapy" (p. 329).

    Review: This study seems to be as far back as we can go with voice therapy before entering the land of stereotypes. This study seemingly refutes the previous idea that training word choice could help with voice feminization. Needless to say, we no longer believe language use has much weight, likely thanks to studies like these.