Our vocal cords are part of the larynx and are primarily used to produce speech. They vibrate when we expel air from the lungs and cause a drop in pressure. This is what enables us to create different tones. High-pitched tones are created when the muscles in the larynx are tight, while lower pitches are achieved when the same muscles are loose. Men generally have longer vocal cords, which means that they have deeper voices.
The audibility of the tones depends on the intensity of the air flow. The resonating cavity between the throat, oral cavity and nasal cavity is essential for timbre modification and tone coloring.
Combined, the vocal cords, air flow and resonating cavity create the ‘instrument’ that we use to make sound, and are responsible for the unique vocal characteristics of every single voice.