Trans Voice Literature Review Part 5

A quick look at a few more articles.

  1. Purcell, D. W., & Munhall, K. G. (2006). Adaptive control of vowel formant frequency: Evidence from real-time formant manipulation. The Journal of the Acoustical Society of America, 120(2), 966-977. https://doi.org/10.1121/1.2217714

    TL;DR: Ten participants were played back their own voices in realtime, but with F1 either pitched up or down by at least 60Hz. The participants compensated in the opposite direction. Following the ramp up or down, the participants would slowly go back to their original F1 via exponential decay. Author conclusion is that formant production is sensitive to auditory feedback.

  2. Schwarz, K., Carla, A. C., Poli, M. S., Anna Paula Villas-Boas, Costa, A. B., Anna Martha, V. F., Bruna, C. G., Dhiordan Cardoso, d. S., Maiko, A. S., & Rodrigues Lobato, M. I. (2023). Speech therapy for transgender women: an updated systematic review and meta-analysis. Systematic Reviews, 12, 1-19. https://doi.org/10.1186/s13643-023-02267-5

    TL;DR: Lit review looked at 16 studies: ten covered surgery, six covered speech therapy. Phonosurgery is significantly more effecting in altering F0 than speech therapy (Spontaneous speech: 39.09Hz surgery, 25.42Hz therapy).

  3. Povinelli, K. C. & Zhao, Y. (2024), Springboard, Roadblock or “Crutch”?: How Transgender Users Leverage Voice Changers for Gender Presentation in Social Virtual Reality, 2024 IEEE Conference Virtual Reality and 3D User Interfaces (VR), Orlando, FL, USA, 354-364. https://doi.org/10.1109/VR58804.2024.00057

    TL;DR: 13 trans people were interviewed on their use of VR and voice changer software. Using a voice changer helped motivate voice training and reduced dysphoria and voice-related harassment.

    As a Support for Voice Training: “Given the arduous process of voice training and difficulties with measuring intermediary success, TGNC individuals have developed communities, applications, and online video-based and text-base guides for voice training techniques,” (p. 361). Historic: “Melanie Speaks!” - the first full series on transgender voice training on VHS in 1993/1996. Current: TransVoiceLessons on YouTube, r/transvoice wiki, and various discord servers.

    Review: While this paper’s aims aren’t quite aligned with the goal of this literature review, the support section helped provide both historical context as well as what trans people are actually doing as opposed to what academia or SLPs have to offer.

  4. Kim, H. T. (2020). Vocal Feminization for Transgender Women: Current Strategies and Patient Perspectives. International Journal of General Medicine, 13, 43–52. https://doi.org/10.2147/IJGM.S205102

    TL;DR: Lit review covering efficacy of surgery and voice therapy.

    Background: The process of increasing F2 can spontaneously raise F0. Most treatments see results of F0 between 145Hz and 155Hz, still well within the masculine range (feminine F0 is at minimum 180Hz). Participants who already had an F0 above 140Hz had the best chance of achieving satisfactory voice feminization. F1 is associated with changes in mouth opening, F2 is associated with changes in the size of the oral cavity, and F3 is associated with front or back construction of the low pharyngeal area.

    Review: I’m intentionally omitting the surgical discussion for now. I’ll come back and edit this later if I expand the objective of this literature review to encompass surgical options.

  5. Neuhaus, T. J., Scherer, R. C., & Whitfield, J. A. (2024). Gender Perception of Speech: Dependence on Fundamental Frequency, Implied Vocal Tract Length, and Source Spectral Tilt. Journal of Voice. https://doi.org/10.1016/j.jvoice.2024.01.014

    TL;DR: Audio files were created from scratch with vocal synthesizers, then presented to 23 presumably non-SLP listeners. The variables (Spectral tilt, F0, implied vocal tract length [VTL]) did not have a uniform relationship with gender. Spectral tilt effect was conditional on Implied Vocal Tract Length: a more negative spectral tilt was associated with perceptual femininity when implied vocal tract length was already short.

    Background: Implied Vocal Tract Length = FF1-6 values.

    Methodology: Values of FF1-3 used for VTL for the vowel /ɑ/ and /i/:

    Vowel VTL (cm) F1 (Hz) F2 (Hz) F3 (Hz)
    /ɑ/ 15.33 850.00 1220.00 2810.00
    /ɑ/ 15.96 818.27 1186.11 2712.55
    /ɑ/ 16.29 802.85 1169.53 2665.09
    /ɑ/ 16.62 787.36 1153.17 2618.47
    /ɑ/ 16.96 772.87 1137.04 2572.67
    /ɑ/ 17.30 758.31 1121.14 2527.66
    /ɑ/ 18.01 730.00 1090.00 2440.00
    /i/ 15.33 310.00 2790.00 3310.00
    /i/ 15.96 299.48 2655.60 3232.31
    /i/ 16.29 294.35 2590.84 3194.15
    /i/ 16.62 289.31 2527.67 3156.44
    /i/ 16.96 284.36 2466.03 3119.17
    /i/ 17.30 279.49 2405.90 3082.35
    /i/ 18.01 270.00 2290.00 3010.00

    My extrapolation from the results: Figure 2B shows that more negative Spectral Tilt brings VTL 15.33cm through 16.29cm to a higher feminine rating. At 190Hz F0, those same VTL were at least rated 50% feminine or greater regardless of Spectral Tilt.

    Review: The authors admit that some of the participants had issues due to the obvious computer generated nature of the audio. And generally speaking, there were issues with participants being able to gender recordings at all. One of their principle findings is that listeners have a tendency to respond “male” when unsure. Comparing the formant values used for VTL against Hillenbrand et al. [1.a], we find that for /ɑ/, every F2 values is lower than the masc F2, while VTL 15.33-16.62 are above masc F1 but below fem F1; for /i/, F2 is above fem for 15.33, and below masc for 18.01, F1 was below masc for all VTL.

  6. Fernandes, I. R. M. (2024). Abordagem ao Género Vocal e do Treino de Femenização Vocal (Master’s Thesis, Universidade do Porto). ProQuest Number: 31613539 https://doi.org/10216/159749

    TL;DR: Seven trans women underwent voice feminization training, consisting of SOVT (bubble phonation), melodic curve (intonational variation and reducing downward shifts, upper inflections at ends of phrases), and aiming towards sympathetic vibrations localized to the maxilla. Trans men were also recorded for comparison without voice training. An unspecified number of on-SLP raters rated recordings on a five point scale from masculine to feminine. Training program showed no significant effect; voice gender was associated with F0, residual H1, and iVTL.

    Background: Spectral Tilt is the difference in amplitude between the first and second harmonic; lower values associated with glottal open quotient and perceptual masculinity.

    Review: The background research is pretty robust, yet the outcome seems almost impossibly minimal: F0 increase of 0.7Hz, iVTL decrease of 0.1cm.

  7. Howerton, C. E., Buckley, D. P., Dahl, K. L., & Stepp, C. E. (2024). The Effects of Speaker Head Posture on Auditory Perception of Vocal Masculinity. Journal of Voice. https://doi.org/10.1016/j.jvoice.2024.08.001

    TL;DR: Twelve cis women were recorded, and another twelve cis women were raters. Speech in the flexed position (chin down to collar bone) was perceived as more masculine, extended had no effect.

  8. Houle, N., Goudelias, D., Lerario, M. P., & Levi, S. V. (2022). Effect of anchor term on auditory-perceptual ratings of feminine and masculine speakers. Journal of Speech, Language, and Hearing Research, 65(6), 2064-2080. https://doi.org/10.1044/2022_JSLHR-21-00476

    TL;DR: 24 speakers (8 cis male, 8 cis female, 8 trans female) were rated by 105 non-SLP raters. No training administered.

    Results: High F0 correlated with femininity; F2 was mostly associated with gender in phonated speech but not whispered speech - F2 might be the lowest frequency in whispered speech and so take the place of F0; Smoothed cepstral peak prominence (CPPs) had basically no correlation.