Each time we inhale (breathe in), air goes into our nose or mouth, then through the larynx, down the trachea, and into our lungs. When we exhale (breathe out), the air goes the other way. When we breathe, the vocal cords relax and air moves through the space between them without making a sound.
When we talk, the vocal cords tighten up and move closer together. Air from the lungs is forced between them and makes them vibrate, producing the sound of our voice. The tongue, lips, and teeth form this sound into words.
The larynx is also sometimes called the voice box.