The larnyx, or "voice box," is an air passage, the gateway from your mouth into your lungs. It is made of cartilage and muscle and 2 membranes called the vocal chords. As you breathe in, fresh air passes down the larnyx and into your lungs. As you breathe out, stale air is forced past the vocal chords causing them to vibrate which creates the sounds of speech.
Click HERE to see the vocal chords in action.