It involves four processes: Initiation,
phonation, oro-nasal process and articulation.
The initiation process is the moment when the air is expelled from the
lungs. In English, speech sounds are the result of “a pulmonic egressive air
stream” (Giegerich, 1992) although that is not the case in all languages
(ingressive sounds).
The phonation process occurs at the larynx. The larynx has two
horizontal folds of tissue in the passage of air; they are the vocal folds. The gap
between these folds is called the glottis.