Changes in a man's voice, unlike a woman's, occur during puberty. Indeed, it is the hormones that cause the thickening of the vocal cords during puberty in men, which gives the voice a lower frequency.

To achieve feminization of her voice, a transgender woman will need the help of speech therapists. The expertise of these professionals concerns in particular everything related to the voice and the structures that make it possible to produce it.

Several physiological structures are called upon to produce the sound of the voice.

The voice works like a wind musical instrument, making the air you breathe vibrate. When inhaling air, it enters the lungs. When exhaling, the air is pushed out. Going up along the trachea, it vibrates the vocal cords; which produces the sound which is modified at the level of the throat and the mouth. It is therefore the size of these two parts of the body that will influence the timbre of the voice.

To transform the sound of the voice into words, it is the articulation that involves the participation of the lips, the jaws and the tongue. The characteristics of the voice appeal to the rules of prosody as its rhythm, stress and length of syllables which vary according to the speaking style of the speaker.

Feminizing hormone therapy has very little influence on the voice of transgender women. This means that their voice retains a rather deep tone that is normally associated with the male gender.

The goal of voice feminization in speech therapy is to use different techniques to adapt the voice to feminine tones. Thus the transgender woman can express herself in a way that is closer to her identity and the image she wishes to project.

During feminization exercises, several aspects of communication are worked on :

1. Voice production: intonation, tone and resonance

2. Articulation, a parameter of speech, so that it is clearer in transgender women

3. The choice of words and vocabulary that have an unsuspected impact on gender recognition

4. Non-verbal language, which also varies by gender

The objective of these exercises is to allow the transgender person to use their vocal apparatus differently and, above all, to enable them to do so in a safe manner. If voice changes are made too abruptly and without professional guidance, there is a risk of vocal overstrain which can cause vocal cord damage. The speech therapist accompanies the transgender woman throughout the process, which generally takes several months, always trying to avoid vocal fatigue.

So, during the feminization of the voice, we do not change anything in the vocal apparatus but we learn to use it in another way.

Voice changing refers to non-surgical techniques employed to alter the human voice. There are several frequencies or harmonics that occur at the lips. The fundamental frequency (F0) or the number of times per second that the vocal cords vibrate (in hertz), the usual frequency for a conversation is around 200 Hz for adult cisgender women and 125 Hz for adult cisgender men.

An evaluation of the use of the voice and its possibilities in terms of tone, is carried out using an acoustic measuring device. However, the acoustic results may differ from the perception (listening to the voice) of the pitch and pitch variation. What you hear is more important than the acoustic results. The doctor also analyzes the daily use of the voice and assesses, in addition to the pitch, the sound power and quality of the voice as well as the adequacy of breathing and resonance.

Speech therapy consists of learning very gradually to speak more acutely. After learning to hear the differences in tone, we move from sounds to words, practicing reading automatic series (numbers, days of the week, names of the months of the year, etc.), then we participate in conversations to speak spontaneously during real discussion situations. The treatment can also address other aspects such as pitch variation, articulation and resonance. The feminization sessions are mainly devoted to the exchange of advice on the analysis of the reports. Exercises should be done at home.

The purpose of the exercises is not to learn to speak as high-pitched as possible. The voice would then sound very unnatural and would also be difficult to sustain. This would also represent a risk of degradation of the vocal cords due to tension (dysphonia). During all these exercises, we will try to make her voice high enough so that it does not clash with her feminine external appearance. 40 Hz represents a realistic increase. Studies have shown that trans women are considered by listeners to be talkers when they can sustain an average pitch above 155 to 160 Hz.

Voice feminization surgery is another possibility which is however not recommended because experience shows that most transgender women operated on obtain a "robot" voice.

The most common surgery is glottoplasty according to Wendler, which is discouraged by a large number of speech therapists. Some, such as Mariela Astudillo in particular, claim that this surgery should be totally prohibited because its effects are negative and harmful on the vocal cords, on the vocal gesture and on the larynx. Indeed, during this operation, the tension of the vocal cords is increased, their consistency and mass are reduced. These effects are obtained by the creation of an anterior webbing. If necessary, an Adam's apple reduction is performed.