The human being produces a sound in its Tract vocal by displacing air of its lungs (while expiring); this air passes through the vocal Cords then of the oral Cavité and/or the nasal Cavité.

The produced sound characteristics are controlled by the expired air flow, the tension on the vocal cords, and forms it vocal tract (Langue, Bouche, Mâchoire).

One classifies the sounds produced in four big classes:

1. its sound voiced;
2. its deaf /non voiced;
3. its occlusive;
4. its fricative.

See too

• Phonetic