Airstream Mechanism
In phonetics, the airstream mechanism is the method by which airflow is created in the vocal tract. Along with phonation, it is one of two mandatory aspects of sound production; without these, there can be no speech sound. The organ generating the airstream is called the initiator; for this reason the production of airflow is called initiation. There are three initiators used in spoken human languages: the diaphragm together with the ribs and lungs (pulmonic mechanisms), the glottis (glottalic mechanisms), and the tongue (lingual or "velaric" mechanisms).
Any 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 and ingressive mechanisms; however, ingressive mechanisms often only reduce outward airflow, and even when air flows into the mouth, it always passes out past the glottis. Of these six possible airstream mechanisms, four are found in words around the world: pulmonic egressive, where the air is pushed out of the lungs by the ribs and diaphragm. All human languages employ such sounds (such as vowels), and nearly three out of four use them exclusively. glottalic egressive, where the air column is pushed upward by the glottis. Such consonants are called ejectives. Ejective and ejective-like consonants occur in 16% of the languages. glottalic ingressive, where the air column is rarefied as the glottis moves downward. Such consonants are called implosives. Implosive and implosive-like consonants occur in 13% of the world's languages. lingual ingressive, AKA velaric ingressive, where the air in the mouth is rarefied by a downward movement of the tongue. These are the clicks. Clicks are regular sounds in ordinary words in fewer than 2% of the world's languages, all but one in Africa.[1] These mechanisms may be combined into airstream contours, such as
Any 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 and ingressive mechanisms; however, ingressive mechanisms often only reduce outward airflow, and even when air flows into the mouth, it always passes out past the glottis. Of these six possible airstream mechanisms, four are found in words around the world: pulmonic egressive, where the air is pushed out of the lungs by the ribs and diaphragm. All human languages employ such sounds (such as vowels), and nearly three out of four use them exclusively. glottalic egressive, where the air column is pushed upward by the glottis. Such consonants are called ejectives. Ejective and ejective-like consonants occur in 16% of the languages. glottalic ingressive, where the air column is rarefied as the glottis moves downward. Such consonants are called implosives. Implosive and implosive-like consonants occur in 13% of the world's languages. lingual ingressive, AKA velaric ingressive, where the air in the mouth is rarefied by a downward movement of the tongue. These are the clicks. Clicks are regular sounds in ordinary words in fewer than 2% of the world's languages, all but one in Africa.[1] These mechanisms may be combined into airstream contours, such as