You Asked:

How are we able to speak? — Mudabir, Iahore, Pakistan

Marshall Brain Answers:

First a little anatomy. You have your lungs. The lungs connect to the wind pipe or trachea. At the top of the trachea is the larynx, also known as the voice box. The larynx is visible in the form of the adam’s apple, and it contains the vocal cords. This video will give you more detail on your larynx.

The process that we call speech starts in the vocal cords. The vocal cords are muscles and cartilage that can close across the air passage. Normally these muscles are relaxed so you can breathe easily. When you want to speak, the muscles tighten across the air passage. When you push air through the tightened vocal cords, they vibrate and create sounds. The tone of the sound and the amount of sound depends on the tightness and the amount of air you push through them.

In this video, a camera is pointing down into the larynx so you can see the vocal cords in action:

Once the sound comes out of the larynx, you shape it with your mouth – your cheeks, tongue and lips can all have effects. If you try to make a “p” sound without using your lips, you see the effect your lips have. If you try to make a “t” sound without your tongue, you can see the effect the tongue has. Try to make an “ooo” sound and you can feel your cheeks getting into the action.

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