Pitch

The acoustic characteristic corresponding with the perceptual feature pitch is the fundamental frequency of the sound wave: the frequency of vibration of the vocal folds. This frequency is dependent on the air pressure from the lungs and the tension and position of the muscles controlling the vocal folds.

Pitch level also depends on intensity: Frequency changes when the sound level decreases or increases.

Links

 * Utrecht Lexicon of Linguistics
 * Tutorial on pitch scales
 * Audio demonstration on pitch and intensity