Editing Phonetics (section)

===The larynx===
{{further|Larynx}}
[[File:Larynx (top view).jpg|thumb|A top-down view of the larynx|alt=See caption]]
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The larynx, commonly known as the "voice box", is a cartilaginous structure in the [[trachea]] responsible for [[phonation]]. The vocal folds (chords) are held together so that they vibrate, or held apart so that they do not. The positions of the vocal folds are achieved by movement of the [[arytenoid cartilage]]s.{{sfn|Ladefoged|2001|p=123}} The [[Larynx#Intrinsic|intrinsic laryngeal muscles]] are responsible for moving the arytenoid cartilages as well as modulating the tension of the vocal folds.{{sfn|Seikel|Drumright|King|2016|p=222}} If the vocal folds are not close or tense enough, they will either vibrate sporadically or not at all. If they vibrate sporadically it will result in either creaky or breathy voice, depending on the degree; if do not vibrate at all, the result will be [[voicelessness]].

In addition to correctly positioning the vocal folds, there must also be air flowing across them or they will not vibrate. The difference in pressure across the glottis required for voicing is estimated at 1 – 2 [[Centimetre of water|cm H<sub>2</sub>O]] (98.0665 – 196.133 pascals<!--this conversion is based on page 47 of https://physics.nist.gov/cuu/pdf/sp811.pdf-->).{{sfn|Ohala|1997|p=1}} The pressure differential can fall below levels required for phonation either because of an increase in pressure above the glottis (superglottal pressure) or a decrease in pressure below the glottis (subglottal pressure). The subglottal pressure is maintained by the [[respiratory muscles]]. Supraglottal pressure, with no constrictions or articulations, is equal to about [[atmospheric pressure]]. However, because articulations—especially consonants—represent constrictions of the airflow, the pressure in the cavity behind those constrictions can increase resulting in a higher supraglottal pressure.{{sfn|Chomsky|Halle|1968|pp=300–301}}