Your voice is made in a small box in the throat (the larynx). Inside it are two soft folds of flesh — people call them vocal cords, though actually they are more like folds than strings. The little space between those two folds is the glottis. When the space is open, air from the lungs can pass through quietly. When the folds come together and the air pushes them apart again and again, they shake, and that shaking is the sound of your voice. Shut the glottis hard, just for a moment, and you get the small catch in the middle of uh-oh. This is a doctor's word and a language teacher's word; you will almost never hear it in the street. It is one glottis in each person.

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