Phonetics Summary

556 WordsOct 22, 20113 Pages
Air-Stream Mechanisms In phonetics, the airstream mechanism is the method by which airflow is created in the vocal tract. Within the vocal tract there are five cavities: oral, nasal pharyngeal, pulmonic, and esophageal. These, during the processes of closure (stop), connect passageways of air, and in this way form air chambers. Air chambers are divided into: 1) active, which contain the air stream. These sometimes become side chambers, when the air stream does not pass directly through the cavity; 2) passive – the air stream does not pass through the cavity fully. A passive chamber is also semipassive when due to become active during the next sound. The organ generating the airstream is called the initiator; for this reason the production of airflow is called initiation. There are three main initiators used in spoken human languages: • the diaphragm together with the ribs and lungs (pulmonic mechanisms), • the glottis (pharynx) (glottalic (pharyngeal) mechanisms), and • the tongue (lingual or "velaric" mechanisms). Each of the three initiators − diaphragm, glottis or tongue − may act by either increasing pressure in the airstream or by reducing it with suction. These changes in pressure are often said to involve outward and inward airflow, and are therefore termed egressive (compressive) and ingressive (rarefactive) mechanisms; however, ingressive mechanisms often only reduce outward airflow. Three air-stream mechanisms may be considered to be major and minor. Major air-stream mechanisms include pulmonic, pharyngeal and oral mechanisms. Pulmonic air-stream mechanism produces pulmonic sounds with lung air. During the natural process, the diaphragm is either raised by muscular action, causing the lungs to contract, or the diaphragm is lowered by muscular action, causing an increase in lung capacity. The subsequent reduction of

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