Airstream mechanism

In phonetics, the airstream mechanism is the method by which airflow is created in the vocal tract. Along with phonation and articulation, it is one of three main components of speech production. The airstream mechanism is mandatory for most sound production and constitutes the first part of this process, which is called initiation. The organ generating the airstream is called the initiator and there are three initiators used phonemically in non-disordered human oral languages: the diaphragm together with the ribs and lungs (pulmonic mechanisms), the glottis (glottalic mechanisms), and the tongue (lingual or "velaric" mechanisms). There are also methods of making sounds that do not require the glottis. These mechanisms are collectively called alaryngeal speech mechanisms (none of these speech mechanisms are used in non-disordered speech): the cheeks (buccal mechanisms, notated {ↀ} in VoQS). See buccal speech. after a laryngectomy, the esophagus may be used (notated {Œ} for simple esophageal speech, {Ю} for tracheo-esophageal speech in VoQS, and notated {И} for electrolaryngeal speech). See esophageal speech. the pharynx, and replacing the glottis using the tongue and the upper alveolus, the palate, or the pharyngeal wall. See pharyngeal speech. Percussive consonants are produced without any airstream mechanism. Any of the three principal initiators − diaphragm, glottis or tongue − may act by either increasing or decreasing the pressure generating the airstream. These changes in pressure often correspond to outward and inward airflow, and are therefore termed egressive and ingressive respectively. Of these six resulting airstream mechanisms, four are found lexically 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 compressed as the glottis moves upward. Such consonants are called ejectives.