Editing Vocal cords (section)

=== Oscillation ===
[[File:Vocal fold animated.gif|thumb|The vocal folds in motion]]
The larynx is a major (but not the only) source of sound in [[speech]], generating sound through the rhythmic opening and closing of the vocal folds.  To oscillate, the vocal folds are brought near enough together such that air pressure builds up beneath the larynx.  The folds are pushed apart by this increased subglottal pressure, with the inferior part of each fold leading the superior part. Such a wave-like motion causes a transfer of energy from the airflow to the fold tissues.<ref>{{Cite journal|title = The minimum lung pressure to sustain vocal fold oscillation|last = Lucero|first = J.C.|date = 1995|journal = Journal of the Acoustical Society of America|doi = 10.1121/1.414354|pmid = 7642816|volume = 98|issue = 2|pages = 779–784|bibcode = 1995ASAJ...98..779L|s2cid = 24053484}}</ref> Under the correct conditions, the energy transferred to the tissues is large enough to overcome losses by dissipation and the oscillation pattern will sustain itself.  In essence, sound is generated in the larynx by chopping up a steady flow of air into little puffs of sound waves.<ref>{{cite journal |author=Titze IR |title=The physics of small-amplitude oscillation of the vocal folds |journal=J. Acoust. Soc. Am. |volume=83 |issue=4 |pages=1536–52 |date=April 1988 |pmid=3372869 |doi=10.1121/1.395910|bibcode=1988ASAJ...83.1536T |s2cid=17809084 }}</ref>

The perceived pitch of a person's voice is determined by a number of different factors, most importantly the [[fundamental frequency]] of the sound generated by the larynx.  The fundamental frequency is influenced by the length, size, and tension of the vocal folds.  This frequency averages about 125 [[hertz|Hz]] in an adult male, 210&nbsp;Hz in adult females, and over 300&nbsp;Hz in children. [[Depth-Kymography|Depth-kymography]]<ref>{{cite journal |vauthors=George NA, de Mul FF, Qiu Q, Rakhorst G, Schutte HK |title=Depth-kymography: high-speed calibrated 3D imaging of human vocal fold vibration dynamics |journal=Phys Med Biol |volume=53 |issue=10 |pages=2667–75 |date=May 2008 |pmid=18443389 |doi=10.1088/0031-9155/53/10/015 |bibcode=2008PMB....53.2667G |s2cid=206007976 }}</ref> is an imaging method to visualize the complex horizontal and vertical movements of vocal folds.

The vocal folds generate a sound rich in [[harmonic]]s.  The harmonics are produced by collisions of the vocal folds with themselves, by recirculation of some of the air back through the trachea, or both.<ref>Ingo Titze, University of Iowa.</ref> Some singers can isolate some of those harmonics in a way that is perceived as [[singing]] in more than one pitch at the same time—a technique called [[overtone singing]] or throat singing such as in the tradition of [[Tuvan throat singing]].