Changes in voice typically begin over the first year and finalize over the second year. These changes involve a deepening of your voice as your laryngeal cartilages respond to therapy. You may notice your voice cracking over the first year, this is normal and a sign that the abrupt changes are starting to occur. By the end of this transition, your voice should drop to a pitch about an octave lower than where it started.
Once these changes finalize, they cannot be reversed if therapy is stopped.
Laryngeal cartilages are located in your throat at the opening of your trachea. These cartilages are involved in voice production. These include your vocal cords.
The trachea is your main airway that divides in order to bring air into your lungs.
The green slit taken through the anatomy of the laryngeal cartilages signal where the vocal chords lie.
Anatomy & Orientation
Ghosted Throat Anatomy
The illustration of the face and neck depicts the anatomy of your throat. Here you will notice that a green square is slit through the laryngeal cartilages where your vocal cords lie. A aerial view cross section of these cartilages can be seen below.
THE VOCAL CHORDS
Anatomy & Orientation
The Vocal Chords from an Above View
Shorter vocal chord length
Shorter rima glottis diameter
Thinner laryngeal cartilages
Less prominent thyroid cartilage
Longer vocal chord length
Larger rima glottis diameter
Thicker laryngeal cartilages
More prominent thyroid cartilage
These illustrations depict the anatomy of your vocal chords and their surrounding cartilages. If someone were to take a camera and look down into your trachea, you would see these structures like this (except they would be covered in protective pink coverings, otherwise known as mucosa). The green slit taken through the trachea in the image shown earlier depicts where these structures lie.
Take a look at the structures labelled vocal chord and rima glottis. When you speak, air travels through the rima glottis and your vocal chords vibrate. Now when your voice deepens from hormone therapy, the space of the rima glottis nearly doubles in diameter. Your vocal chords lengthen and your surrounding cartilages become thicker. This allows your voice to drop close to an octave in pitch.
Now look at the area labelled "thyroid cartilage". This is located towards the front. If you place your fingers along the front and center of your neck, right under your jaw, you can feel your thyroid cartilage as the bumpy cartilage that sticks out. In biological males, this develops into an Adam's Apple during puberty. As mentioned before, it is unclear if the development of an Adam's Apple occurs from hormone therapy.
The vocal chords, also known as vocal folds, are two chord-like pieces of cartilages that span the length of your laryngeal cartilages. When you speak, these chords vibrate as air passes, allowing you to modify the sound of your voice.
Mucosa is a pink protective covering that lines your mouth and travels down the lining of your throat. You can see mucosa when you open your mouth and look into your throat using a mirror. Its not shown in the images above.
The rima glottis is the space that lies between the two vocal cords. When the diameter of this space doubles, it allows the voice to deepen.
The thyroid cartilage is the same cartilage of the “Adam’s Apple” in biological males. Although there are few studies that examine this occurring in testosterone therapy, it is something to look out for as your voice changes. Remember this is not guaranteed to occur.