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The term phonation has slightly different meanings depending on the subfield of
phonetics Phonetics is a branch of linguistics that studies how humans produce and perceive sounds, or in the case of sign languages, the equivalent aspects of sign. Linguists who specialize in studying the physical properties of speech are phoneticians. ...
. Among some phoneticians, ''phonation'' is the process by which the
vocal folds In humans, vocal cords, also known as vocal folds or voice reeds, are folds of throat tissues that are key in creating sounds through vocalization. The size of vocal cords affects the pitch of voice. Open when breathing and vibrating for speec ...
produce certain sounds through quasi-periodic vibration. This is the definition used among those who study laryngeal anatomy and physiology and speech production in general. Phoneticians in other subfields, such as linguistic phonetics, call this process '' voicing'', and use the term ''phonation'' to refer to any oscillatory state of any part of the larynx that modifies the airstream, of which voicing is just one example. Voiceless and supra-glottal phonations are included under this definition.


Voicing

The phonatory process, or voicing, occurs when air is expelled from the lungs through the
glottis The glottis is the opening between the vocal folds (the rima glottidis). The glottis is crucial in producing vowels and voiced consonants. Etymology From Ancient Greek ''γλωττίς'' (glōttís), derived from ''γλῶττα'' (glôtta), v ...
, creating a pressure drop across the larynx. When this drop becomes sufficiently large, the vocal folds start to oscillate. The minimum pressure drop required to achieve phonation is called the phonation threshold pressure (PTP), and for humans with normal vocal folds, it is approximately 2–3 cm H2O. The motion of the vocal folds during oscillation is mostly lateral, though there is also some superior component as well. However, there is almost no motion along the length of the vocal folds. The oscillation of the vocal folds serves to modulate the pressure and flow of the air through the larynx, and this modulated airflow is the main component of the sound of most voiced
phones A telephone is a telecommunications device that permits two or more users to conduct a conversation when they are too far apart to be easily heard directly. A telephone converts sound, typically and most efficiently the human voice, into ele ...
. The sound that the larynx produces is a harmonic series. In other words, it consists of a fundamental tone (called the fundamental frequency, the main acoustic cue for the percept pitch) accompanied by harmonic overtones, which are multiples of the fundamental frequency. According to the source–filter theory, the resulting sound excites the resonance chamber that is the
vocal tract The vocal tract is the cavity in human bodies and in animals where the sound produced at the sound source ( larynx in mammals; syrinx in birds) is filtered. In birds it consists of the trachea, the syrinx, the oral cavity, the upper part of th ...
to produce the individual speech sounds. The vocal folds will not oscillate if they are not sufficiently close to one another, are not under sufficient tension or under too much tension, or if the pressure drop across the larynx is not sufficiently large. In linguistics, a phone is called
voiceless In linguistics, voicelessness is the property of sounds being pronounced without the larynx vibrating. Phonologically, it is a type of phonation, which contrasts with other states of the larynx, but some object that the word phonation implies ...
if there is no phonation during its occurrence. In speech, voiceless phones are associated with vocal folds that are elongated, highly tensed, and placed laterally (abducted) when compared to vocal folds during phonation. Fundamental frequency, the main acoustic cue for the percept ''pitch'', can be varied through a variety of means. Large scale changes are accomplished by increasing the tension in the vocal folds through contraction of the
cricothyroid muscle The cricothyroid muscle is the only tensor muscle of the larynx aiding with phonation. It is innervated by the superior laryngeal nerve. Its action tilts the thyroid forward to help tense the vocal cords. Structure The cricothyroid muscle ...
. Smaller changes in tension can be effected by contraction of the thyroarytenoid muscle or changes in the relative position of the thyroid and
cricoid cartilage The cricoid cartilage , or simply cricoid (from the Greek ''krikoeides'' meaning "ring-shaped") or cricoid ring, is the only complete ring of cartilage around the trachea. It forms the back part of the voice box and functions as an attachment si ...
s, as may occur when the larynx is lowered or raised, either volitionally or through movement of the tongue to which the larynx is attached via the hyoid bone. In addition to tension changes, fundamental frequency is also affected by the pressure drop across the larynx, which is mostly affected by the pressure in the lungs, and will also vary with the distance between the vocal folds. Variation in fundamental frequency is used linguistically to produce intonation and tone. There are currently two main theories as to how vibration of the
vocal folds In humans, vocal cords, also known as vocal folds or voice reeds, are folds of throat tissues that are key in creating sounds through vocalization. The size of vocal cords affects the pitch of voice. Open when breathing and vibrating for speec ...
is initiated: the myoelastic theory and the aerodynamic theory.Titze, I. R. (2006). The Myoelastic Aerodynamic Theory of Phonation, Iowa City:National Center for Voice and Speech, 2006. These two theories are not in contention with one another and it is quite possible that both theories are true and operating simultaneously to initiate and maintain vibration. A third theory, the neurochronaxic theory, was in considerable vogue in the 1950s, but has since been largely discredited.


Myoelastic and aerodynamic theory

The myoelastic theory states that when the vocal cords are brought together and breath pressure is applied to them, the cords remain closed until the pressure beneath them, the subglottic pressure, is sufficient to push them apart, allowing air to escape and reducing the pressure enough for the muscle tension recoil to pull the folds back together again. The pressure builds up once again until the cords are pushed apart, and the whole cycle keeps repeating itself. The rate at which the cords open and close, the number of cycles per second, determines the pitch of the phonation. The aerodynamic theory is based on the Bernoulli energy law in fluids. The theory states that when a stream of breath is flowing through the
glottis The glottis is the opening between the vocal folds (the rima glottidis). The glottis is crucial in producing vowels and voiced consonants. Etymology From Ancient Greek ''γλωττίς'' (glōttís), derived from ''γλῶττα'' (glôtta), v ...
while the arytenoid cartilages are held together (by the action of the interarytenoid muscles), a push-pull effect is created on the vocal fold tissues that maintains self-sustained oscillation. The push occurs during glottal opening, when the glottis is convergent, and the pull occurs during glottal closing, when the glottis is divergent. Such an effect causes a transfer of energy from the airflow to the vocal fold tissues which overcomes losses by dissipation and sustain the oscillation. The amount of lung pressure needed to begin phonation is defined by Titze as the oscillation threshold pressure. During glottal closure, the air flow is cut off until breath pressure pushes the folds apart and the flow starts up again, causing the cycles to repeat. The textbook entitled Myoelastic Aerodynamic Theory of Phonation by Ingo Titze credits Janwillem van den Berg as the originator of the theory and provides detailed mathematical development of the theory.


Neurochronaxic theory

This theory states that the frequency of the vocal fold vibration is determined by the
chronaxie Chronaxie is the minimum time required for an electric current double the strength of the rheobase to stimulate a muscle or a neuron. Rheobase is the lowest intensity with indefinite pulse duration which just stimulated muscles or nerves. Chrona ...
of the recurrent nerve, and not by breath pressure or muscular tension. Advocates of this theory thought that every single vibration of the vocal folds was due to an impulse from the recurrent laryngeal nerves and that the acoustic center in the brain regulated the speed of vocal fold vibration. Speech and voice scientists have long since abandoned this theory as the muscles have been shown to not be able to contract fast enough to accomplish the vibration. In addition, persons with paralyzed vocal folds can produce phonation, which would not be possible according to this theory. Phonation occurring in excised larynges would also not be possible according to this theory.


State of the glottis

In linguistic phonetic treatments of phonation, such as those of
Peter Ladefoged Peter Nielsen Ladefoged ( , ; 17 September 1925 – 24 January 2006) was a British linguist and phonetician. He was Professor of Phonetics at University of California, Los Angeles (UCLA), where he taught from 1962 to 1991. His book '' A Cour ...
, phonation was considered to be a matter of points on a continuum of tension and closure of the vocal cords. More intricate mechanisms were occasionally described, but they were difficult to investigate, and until recently the state of the glottis and phonation were considered to be nearly synonymous.Ladefoged, Peter& Ian Maddieson. (1996). ''The Sounds of the World's Languages''. Cambridge, MA: Blackwell. If the vocal cords are completely relaxed, with the arytenoid cartilages apart for maximum airflow, the cords do not vibrate. This is voiceless phonation, and is extremely common with obstruents. If the arytenoids are pressed together for glottal closure, the vocal cords block the airstream, producing stop sounds such as the
glottal stop The glottal plosive or stop is a type of consonantal sound used in many spoken languages, produced by obstructing airflow in the vocal tract or, more precisely, the glottis. The symbol in the International Phonetic Alphabet that represents thi ...
. In between there is a sweet spot of maximum vibration. Also, the existence of an optimal glottal shape for ease of phonation has been shown, at which the lung pressure required to initiate the vocal cord vibration is minimum. This is modal voice, and is the normal state for vowels and
sonorant In phonetics and phonology, a sonorant or resonant is a speech sound that is produced with continuous, non-turbulent airflow in the vocal tract; these are the manners of articulation that are most often voiced in the world's languages. Vowels ar ...
s in all the world's languages. However, the aperture of the arytenoid cartilages, and therefore the tension in the vocal cords, is one of degree between the end points of open and closed, and there are several intermediate situations utilized by various languages to make contrasting sounds. For example,
Gujarati Gujarati may refer to: * something of, from, or related to Gujarat, a state of India * Gujarati people, the major ethnic group of Gujarat * Gujarati language, the Indo-Aryan language spoken by them * Gujarati languages, the Western Indo-Aryan sub- ...
has vowels with a partially lax phonation called breathy voice or murmured voice (transcribed in IPA with a subscript umlaut ), while Burmese has vowels with a partially tense phonation called
creaky voice In linguistics, creaky voice (sometimes called laryngealisation, pulse phonation, vocal fry, or glottal fry) refers to a low, scratchy sound that occupies the vocal range below the common vocal register. It is a special kind of phonation in which ...
or laryngealized voice (transcribed in IPA with a subscript tilde ). The Jalapa dialect of Mazatec is unusual in contrasting both with modal voice in a three-way distinction. (Note that Mazatec is a tonal language, so the glottis is making several tonal distinctions simultaneously with the phonation distinctions.) :''Note: There was an editing error in the source of this information. The latter two translations may have been mixed up.'' Javanese does not have modal voice in its stops, but contrasts two other points along the phonation scale, with more moderate departures from modal voice, called
slack voice Slack voice (or lax voice) is the pronunciation of consonant or vowels with a glottal opening slightly wider than that occurring in modal voice. Such sounds are often referred to informally as lenis or half- voiced in the case of consonants. In ...
and stiff voice. The "muddy" consonants in Shanghainese are slack voice; they contrast with tenuis and aspirated consonants. Although each language may be somewhat different, it is convenient to classify these degrees of phonation into discrete categories. A series of seven alveolar stops, with phonations ranging from an open/lax to a closed/tense glottis, are: The IPA diacritics ''under-ring'' and ''subscript wedge'', commonly called "voiceless" and "voiced", are sometimes added to the symbol for a voiced sound to indicate more lax/open (slack) and tense/closed (stiff) states of the glottis, respectively. (Ironically, adding the 'voicing' diacritic to the symbol for a voiced consonant indicates ''less'' modal voicing, not more, because a modally voiced sound is already fully voiced, at its sweet spot, and any further tension in the vocal cords dampens their vibration.) Alsatian, like several Germanic languages, has a typologically unusual phonation in its stops. The consonants transcribed (ambiguously called "lenis") are partially voiced: The vocal cords are positioned as for voicing, but do not actually vibrate. That is, they are technically voiceless, but without the open glottis usually associated with voiceless stops. They contrast with both modally voiced and modally voiceless in French borrowings, as well as aspirated word initially. If the arytenoid cartiledges are parted to admit turbulent airflow, the result is whisper phonation if the vocal folds are adducted, and whispery voice phonation (murmur) if the vocal folds vibrate modally. Whisper phonation is heard in many productions of French ''oui!'', and the "voiceless" vowels of many North American languages are actually whispered.Laver (1994) ''Principles of Phonetics'', p. 189 ff, 296 ff, 344 ff.


Glottal consonants

It has long been noted that in many languages, both phonologically and historically, the
glottal consonant Glottal consonants are consonants using the glottis as their primary articulation. Many phoneticians consider them, or at least the glottal fricative, to be transitional states of the glottis without a point of articulation as other consonants ...
s do not behave like other consonants. Phonetically, they have no manner or place of articulation other than the state of the glottis: ''glottal closure'' for , ''breathy voice'' for , and ''open airstream'' for . Some phoneticians have described these sounds as neither glottal nor consonantal, but instead as instances of pure phonation, at least in many European languages. However, in
Semitic languages The Semitic languages are a branch of the Afroasiatic language family. They are spoken by more than 330 million people across much of West Asia, the Horn of Africa, and latterly North Africa, Malta, West Africa, Chad, and in large immigrant ...
they do appear to be true glottal consonants.


Supra-glottal phonation

In the last few decades it has become apparent that phonation may involve the entire larynx, with as many as six valves and muscles working either independently or together. From the glottis upward, these articulations are: # glottal (the vocal cords), producing the distinctions described above # ventricular (the 'false vocal cords', partially covering and damping the glottis) # arytenoid ( sphincteric compression forwards and upwards) # epiglotto-pharyngeal (retraction of the tongue and
epiglottis The epiglottis is a leaf-shaped flap in the throat that prevents food and water from entering the trachea and the lungs. It stays open during breathing, allowing air into the larynx. During swallowing, it closes to prevent aspiration of food in ...
, potentially closing onto the pharyngeal wall) #raising or lowering of the entire larynx #narrowing of the
pharynx The pharynx (plural: pharynges) is the part of the throat behind the mouth and nasal cavity, and above the oesophagus and trachea (the tubes going down to the stomach and the lungs). It is found in vertebrates and invertebrates, though its st ...
Until the development of fiber-optic
laryngoscopy Laryngoscopy () is endoscopy of the larynx, a part of the throat. It is a medical procedure that is used to obtain a view, for example, of the vocal folds and the glottis. Laryngoscopy may be performed to facilitate tracheal intubation durin ...
, the full involvement of the larynx during speech production was not observable, and the interactions among the six laryngeal articulators is still poorly understood. However, at least two supra-glottal phonations appear to be widespread in the world's languages. These are harsh voice ('ventricular' or 'pressed' voice), which involves overall constriction of the larynx, and
faucalized voice Faucalized voice, also called hollow voice or yawny voice, is a vocal quality of speech production characterized by the vertical expansion of the pharyngeal cavity due to the lowering of the larynx. It is termed ''faucalized'' because of the str ...
('hollow' or 'yawny' voice), which involves overall expansion of the larynx. The Bor dialect of Dinka has contrastive modal, breathy, faucalized, and harsh voice in its vowels, as well as three tones. The ''ad hoc'' diacritics employed in the literature are a subscript double quotation mark for faucalized voice, , and underlining for harsh voice, . Examples are, Other languages with these contrasts are Bai (modal, breathy, and harsh voice), Kabiye (faucalized and harsh voice, previously seen as ±ATR),
Somali Somali may refer to: Horn of Africa * Somalis, an inhabitant or ethnicity associated with Greater Somali Region ** Proto-Somali, the ancestors of modern Somalis ** Somali culture ** Somali cuisine ** Somali language, a Cushitic language ** Somali ...
(breathy and harsh voice). Elements of laryngeal articulation or phonation may occur widely in the world's languages as phonetic detail even when not phonemically contrastive. For example, simultaneous glottal, ventricular, and arytenoid activity (for something other than epiglottal consonants) has been observed in
Tibetan Tibetan may mean: * of, from, or related to Tibet * Tibetan people, an ethnic group * Tibetan language: ** Classical Tibetan, the classical language used also as a contemporary written standard ** Standard Tibetan, the most widely used spoken diale ...
, Korean, Nuuchahnulth, Nlaka'pamux, Thai, Sui, Amis, Pame,
Arabic Arabic (, ' ; , ' or ) is a Semitic language spoken primarily across the Arab world.Semitic languages: an international handbook / edited by Stefan Weninger; in collaboration with Geoffrey Khan, Michael P. Streck, Janet C. E.Watson; Walter ...
, Tigrinya,
Cantonese Cantonese ( zh, t=廣東話, s=广东话, first=t, cy=Gwóngdūng wá) is a language within the Chinese (Sinitic) branch of the Sino-Tibetan languages originating from the city of Guangzhou (historically known as Canton) and its surrounding a ...
, and Yi.


European language examples

In languages such as
French French (french: français(e), link=no) may refer to: * Something of, from, or related to France ** French language, which originated in France, and its various dialects and accents ** French people, a nation and ethnic group identified with Franc ...
and Portuguese, all obstruents occur in pairs, one modally voiced and one voiceless: In
English English usually refers to: * English language * English people English may also refer to: Peoples, culture, and language * ''English'', an adjective for something of, from, or related to England ** English national ...
, every voiced
fricative A fricative is a consonant produced by forcing air through a narrow channel made by placing two articulators close together. These may be the lower lip against the upper teeth, in the case of ; the back of the tongue against the soft palate in ...
corresponds to a voiceless one. For the pairs of English stops, however, the distinction is better specified as voice onset time rather than simply voice: In initial position, /b d g/ are only partially voiced (voicing begins during the hold of the consonant), and /p t k/ are aspirated (voicing begins only well after its release). Certain English
morpheme A morpheme is the smallest meaningful Constituent (linguistics), constituent of a linguistic expression. The field of linguistics, linguistic study dedicated to morphemes is called morphology (linguistics), morphology. In English, morphemes are ...
s have voiced and voiceless allomorphs, such as: the plural, verbal, and possessive endings spelled ''-s'' (voiced in ''kids'' but voiceless in ''kits'' ), and the past-tense ending spelled ''-ed'' (voiced in ''buzzed'' but voiceless in ''fished'' ). A few European languages, such as Finnish, have no phonemically voiced obstruents but pairs of long and short consonants instead. Outside Europe, the lack of voicing distinctions is common; indeed, in
Australian languages The Indigenous languages of Australia number in the hundreds, the precise number being quite uncertain, although there is a range of estimates from a minimum of around 250 (using the technical definition of 'language' as non-mutually intellig ...
it is nearly universal. In languages without the distinction between voiceless and voiced obstruents, they are realized as voiced in voiced environments, such as between vowels, and voiceless elsewhere.


Vocal registers


Phonology

In
phonology Phonology is the branch of linguistics that studies how languages or dialects systematically organize their sounds or, for sign languages, their constituent parts of signs. The term can also refer specifically to the sound or sign system of a ...
, a register is a combination of tone and vowel phonation into a single phonological parameter. For example, among its vowels, Burmese combines modal voice with low tone, breathy voice with falling tone, creaky voice with high tone, and glottal closure with high tone. These four registers contrast with each other, but no other combination of phonation (modal, breath, creak, closed) and tone (high, low, falling) is found.


Pedagogy and speech pathology

Among vocal pedagogues and speech pathologists, a vocal register also refers to a particular phonation limited to a particular range of pitch, which possesses a characteristic sound quality. The term "register" may be used for several distinct aspects of the human voice: *A particular part of the
vocal range Vocal range is the range of pitches that a human voice can phonate. A common application is within the context of singing, where it is used as a defining characteristic for classifying singing voices into voice types. It is also a topic of st ...
, such as the upper, middle, or lower registers, which may be bounded by vocal breaks *A particular phonation *A
resonance Resonance describes the phenomenon of increased amplitude that occurs when the frequency of an applied periodic force (or a Fourier component of it) is equal or close to a natural frequency of the system on which it acts. When an oscil ...
area such as chest voice or head voice *A certain vocal timbre Four combinations of these elements are identified in speech pathology: the vocal fry register, the modal register, the falsetto register, and the whistle register.


See also

* Ballistic syllables *
Breathy voice Breathy voice (also called murmured voice, whispery voice, soughing and susurration) is a phonation in which the vocal folds vibrate, as they do in normal (modal) voicing, but are adjusted to let more air escape which produces a sighing-like ...
*
Creaky voice In linguistics, creaky voice (sometimes called laryngealisation, pulse phonation, vocal fry, or glottal fry) refers to a low, scratchy sound that occupies the vocal range below the common vocal register. It is a special kind of phonation in which ...
*
Faucalized voice Faucalized voice, also called hollow voice or yawny voice, is a vocal quality of speech production characterized by the vertical expansion of the pharyngeal cavity due to the lowering of the larynx. It is termed ''faucalized'' because of the str ...
* Harsh voice * List of language disorders * List of phonetics topics * Modal voice *
Slack voice Slack voice (or lax voice) is the pronunciation of consonant or vowels with a glottal opening slightly wider than that occurring in modal voice. Such sounds are often referred to informally as lenis or half- voiced in the case of consonants. In ...
* Stiff voice * Strident vowel * Vocal resonation * Voice onset time * Voice organ


References


External links


States of the Glottis
(Esling & Harris, University of Victoria)
A video showing phonation in action
{{Authority control Human voice