Essay: Airstream Mechanism
What does it mean by airstream mechanism?
Airstream mechanisms are the methods of lung air movement in which airflow from the lungs or mouth facilitates speech sounds. It is one of the basic components of speech production. Generally, there are three types of airstreams including pulmonic which is initiated by the respiratory muscles of the lungs, glottalic which is initiated by the upward or downward movements of the glottis; and velaric which is initiated by the backward and downward movement of the tongue to the velum.
There are two types of airflow directions: egressive (air is pushed out of the mouth thorugh the vocal tract) and ingressive (air is sucked into the vocal tract through the mouth during part of the articulation). The principle airstream mechanisms are listed in the following:
Brief description: lung air pushed out under control of the respiratory muscles
Specific name for stop consonant: plosive
Vocal cords: voiceless (p,t,k) or voiced (b,d,g)
Brief description: pharynx air compressed by the upward movement of the closed glottis
Specific name for stop consonant: ejective
Vocal cords: voiceless
3. Glottalic ingressive
Brief description: downward movement of the vibrating glottis; pulmonic egressive airstream may also involved
Specific name for stop consonant: implosive
Vocal cords: usually voiced by pulmonic airstream
Brief description: mouth air rarefied by backward and downward movement of the tongue
Specific name for stop consonant: click
Vocal cords: combine with pulmonic airstream
Source: Ladefoged, P. (1993). A course in phonetics. USA: Harcourt Brace.