Phonation

In phonetics, phonation is the "use of the laryngeal system to generate an audible source of acoustic energy, i.e., sound, which can then be modified by the articulatory actions of the rest of the vocal apparatus."

Phonation has traditionally been seen as one dimension of phonetic voicing, the degree of glottal tension. (A second dimension of voicing is timing, called voice onset time, or "VOT". When a sound is described as "half voiced", it may not be clear whether it is quality (phonation) or quantity (VOT) that is referred to.)

However, with recent advances in imaging technology, it has become apparent that in many languages phonation involves more than just the glottis.

Voicing
A voiced sound is produced when air expelled from the lungs causes the vocal folds to vibrate. This produces a fundamental tone accompanied by several non-harmonic overtones. The resulting sound is modified by movements in the vocal tract, by the volume of the airflow and by the degree of constriction of the vocal cords. (During speech the flow of air is relatively small because of constrictions of the vocal cords.) Vowels are usually voiced, as are many consonants.

If the vocal folds are lax and not sufficiently close to vibrate, then the sound (usually a consonant) is voiceless.

The vocal vibration is varied to produce intonation and tone. This is accomplished by varying the pressure of the air column under the glottis as well as the tension in the vocal folds themselves. These actions produce changes in the frequency of vocal-cord vibration, which generates the fundamental pitch of the voice. Tone and intonation are not conveyed well by voiceless sounds, with their lax vocal folds, but the changes in airflow are still audible.

Phonation as the state of the glottis


In classic treatments of phonation, such as those of Peter Ladefoged, 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.

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. In between there is a sweet spot of maximum vibration. This is modal voice, and is the normal state for vowels and sonorants 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 has vowels with a partially lax phonation called breathy voice or murmured, while Burmese has vowels with a partially tense phonation called creaky voice or laryngealized. Both of these phonations have dedicated IPA diacritics, an under-umlaut and under-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 plosives, but contrasts two other points along the phonation scale, with more moderate departures from modal voice, called slack voice 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 plosives, 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.)

Unaccompanied phonation
It has long been noted that, both phonologically and historically, the glottal consonants 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.

Register
Many languages combine phonation and tone into a single phonological system. In Mazatec, tone and phonation have separate lives, so that all possible combinations of its several tones and phonations can be utilized to distinguish words, but Burmese tones do not contrast directly in this way. Rather each Burmese tone occurs only with a specific phonation that serves to make it more distinctive &mdash; or, from a different point of view, Burmese tone serves to make the phonations more distinct. These tone-phonation hybrids are called registers.

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
 * 1) glottal (the vocal cords), producing the distinctions described above
 * 2) ventricular (the 'false vocal cords', partially covering and damping the glottis)
 * 3) arytenoid (sphincteric compression forwards and upwards)
 * 4) epiglotto-pharyngeal (retraction of the tongue and epiglottis, potentially closing onto the pharyngeal wall)
 * 5) raising or lowering of the entire larynx
 * 6) narrowing of the pharynx

Until the development of fiber-optic laryngoscopy, 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 ('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 (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, Korean, Nuuchahnulth, Nlaka’pamux, Thai, Sui, Amis, Pame, Arabic, Tigrinya, Cantonese, and Yi.

Phonation in familiar languages
In languages such as French, all obstruents occur in pairs, one modally voiced and one voiceless.

In English, every voiced fricative corresponds to a voiceless one. For the pairs of English plosives, 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), while /p t k/ are aspirated (voicing doesn't begin until well after its release).

Certain English morphemes 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 or Alemannic, have no phonemically voiced obstruents but pairs of long and short consonants instead. Outside of Europe, a lack of voicing distinctions is not uncommon; indeed, in Australian languages it is nearly universal.