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{{short description|Sound in spoken language, articulated with an open vocal tract}}
{{More footnotes needed|date=November 2017}}
{{IPA vowels|class=floatright}} 
{{IPA notice}}
A '''vowel''' is a speech sound pronounced without any stricture in the [[vocal tract]],{{Sfn|Ladefoged|Maddieson|1996|p=281}} forming the nucleus of a [[syllable]]. Vowels are one of the two principal classes of speech sounds, the other being the [[consonant]]. Vowels vary in quality, in [[loudness]] and also in [[Vowel length|quantity (length)]]. They are usually [[voice (phonetics)|voiced]] and are closely involved in [[Prosody (linguistics)|prosodic]] variation such as [[tone (linguistics)|tone]], [[intonation (linguistics)|intonation]] and [[Stress (linguistics)|stress]].

The word ''vowel'' comes from the [[Latin]] word {{lang|la|vocalis}}, meaning "vocal" (i.e. relating to the voice).<ref name="Vowel Etymology">{{cite web |title=Vowel |url=http://www.etymonline.com/index.php?term=vowel |access-date=12 April 2012 |publisher=Online Etymology Dictionary}}</ref> 
In English, the word ''vowel'' is commonly used to refer both to vowel sounds and to the written symbols that represent them ({{vr|a}}, {{vr|e}}, {{vr|i}}, {{vr|o}}, {{vr|u}}, and sometimes {{vr|w}} and {{vr|y}}).<ref>[[Dictionary.com]]: [https://www.dictionary.com/browse/vowel ''vowel'']</ref>

{{multiple image
| align = right
| direction = vertical
| image1 = Vowel triangle, intermediate vowels.png
| caption1 = An idealized schematic of vowel space, based on the formants of [[Daniel Jones (phonetician)|Daniel Jones]] and [[John C. Wells|John Wells]] pronouncing the cardinal vowels of the IPA. The scale is logarithmic. The grey range is where F2 would be less than F1, which by definition is impossible. {{IPA|[a]}} is an extra-low central vowel. Phonemically it may be front or back, depending on the language. Rounded vowels that are front in tongue position are front-central in formant space, while unrounded vowels that are back in articulation are back-central in formant space. Thus {{IPA|[y ɯ]}} have perhaps similar F1 and F2 values to the high central vowels {{IPA|[ɨ ʉ]}}, being distinguished by rounding (F3); similarly {{IPA|[ø ɤ]}} vs central {{IPA|[ɘ ɵ]}} and {{IPA|[œ ʌ]}} vs central {{IPA|[ɜ ɞ]}}. 
}}

==Definition==
There are two complementary definitions of vowel, one [[Phonetics|phonetic]] and the other [[Phonology|phonological]].
*In the [[phonetic]] definition, a vowel is a sound, such as the [[English language|English]] "ah" {{IPAc-en|ɑː}} or "oh" {{IPAc-en|oʊ}}, produced with an open [[vocal tract]]; it is median (the air escapes along the middle of the tongue), oral (at least some of the airflow must escape through the mouth), [[Frictionless continuant|frictionless]] and [[continuant]].<ref>{{cite book|last1=Cruttenden|first1=Alan|title=Gimson's Pronunciation of English|date=2014|publisher=Routledge|isbn=9781444183092|page=27|edition=Eighth}}</ref> There is no significant build-up of air pressure at any point above the [[glottis]]. This contrasts with [[consonant]]s, such as the English "sh" {{IPA|[ʃ]}}, which have a constriction or closure at some point along the vocal tract. 
*In the phonological definition, a vowel is defined as [[Syllable|syllabic]], the sound that forms the [[syllable nucleus|peak of a syllable]].<ref>{{cite book|last1=Cruttenden|first1=Alan|title=Gimson's Pronunciation of English|date=2014|publisher=Routledge|isbn=9781444183092|page=53|edition=Eighth}}</ref> A phonetically equivalent but non-syllabic sound is a [[semivowel]]. In [[oral language]]s, phonetic vowels normally form the peak (nucleus) of many or all syllables, whereas [[consonant]]s form the [[syllable onset|onset]] and (in languages that have them) [[syllable coda|coda]]. Some languages allow other sounds to form the nucleus of a syllable, such as the [[syllabic consonant|syllabic]] (i.e., vocalic) ''l'' in the English word ''table'' {{IPA|[ˈtʰeɪ.bl̩]}} (when not considered to have a weak vowel sound: {{IPA|[ˈtʰeɪ.bəl]}}) or the syllabic ''r'' in the [[Serbo-Croatian]] word ''vrt'' {{IPA|[ʋr̩̂t]}} "garden".

The phonetic definition of "vowel" (i.e. a sound produced with no constriction in the vocal tract) does not always match the phonological definition (i.e. a sound that forms the peak of a syllable).<ref>Laver, John (1994) ''Principles of Phonetics'', Cambridge: Cambridge University Press, p. 269.</ref> The [[approximant]]s {{IPA|[j]}} and {{IPA|[w]}} illustrate this: both are without much of a constriction in the vocal tract (so phonetically they seem to be vowel-like), but they occur at the onset of syllables (e.g. in "yet" and "wet") which suggests that phonologically they are consonants. A similar debate arises over whether a word like ''bird'' in a [[Rhotic consonant|rhotic]] dialect has an [[r-colored vowel]] {{IPA|/ɝ/}} or a syllabic consonant {{IPA|/ɹ̩/}}. The American linguist [[Kenneth Pike]] (1943) suggested the terms "'''vocoid'''" for a phonetic vowel and "vowel" for a phonological vowel,<ref>Crystal, David (2005) ''A Dictionary of Linguistics & Phonetics (Fifth Edition)'', Maldern, MA/Oxford: Blackwell, p. 494.</ref> so using this terminology, {{IPA|[j]}} and {{IPA|[w]}} are classified as vocoids but not vowels. However, Maddieson and Emmory (1985) demonstrated from a range of languages that semivowels are produced with a narrower constriction of the vocal tract than vowels, and so may be considered consonants on that basis.<ref>{{SOWL|323}}</ref> Nonetheless, the phonetic and phonemic definitions would still conflict for the syllabic /l/ in ''table'' or the syllabic nasals in ''button'' and ''rhythm''.

==Articulation== <!-- This section is linked from [[Danish language]] -->
[[File:Cardinal vowels-Jones x-ray.jpg|thumb|upright=0.9|X-rays of Daniel Jones' {{IPA|[i, u, a, ɑ]|cat=no}}]]
[[File:Vowel quadrilateral (IPA 1949).png|thumb|The original vowel quadrilateral, from Jones' articulation. The vowel trapezoid of the modern IPA, and at the top of this article, is a simplified rendition of this diagram. The bullets are the cardinal vowel points. (A parallel diagram covers the front and central rounded and back unrounded vowels.) The cells indicate the ranges of articulation that could reasonably be transcribed with those cardinal vowel letters, {{IPA|[i, e, ɛ, a, ɑ, ɔ, o, u, ɨ]|cat=no}}, and non-cardinal {{IPA|[ə]}}. If a language distinguishes fewer than these vowel qualities, {{IPA|[e, ɛ]}} could be merged to {{angbr IPA|e}}, {{IPA|[o, ɔ]}} to {{angbr IPA|o}}, {{IPA|[a, ɑ]}} to {{angbr IPA|a}}, etc. If a language distinguishes more, {{angbr IPA|ɪ}} could be added where the ranges of {{IPA|[i, e, ɨ, ə]}} intersect, {{angbr IPA|ʊ}} where {{IPA|[u, o, ɨ, ə]}} intersect, and {{angbr IPA|ɐ}} where {{IPA|[ɛ, ɔ, a, ɑ, ə]}} intersect.]]
The traditional view of vowel production, reflected for example in the terminology and presentation of the [[International Phonetic Alphabet]], is one of [[Articulatory phonetics|articulatory features]] that determine a vowel's ''quality'' as distinguishing it from other vowels. [[Daniel Jones (phonetician)|Daniel Jones]] developed the [[cardinal vowel]] system to describe vowels in terms of the features of tongue ''height'' (vertical dimension), tongue ''backness'' (horizontal dimension) and ''roundedness'' (lip articulation). These three parameters are indicated in the schematic quadrilateral IPA [[vowel diagram]] on the right. There are additional features of vowel quality, such as the [[soft palate|velum]] position (nasality), type of [[vocal fold]] vibration (phonation), and tongue root position.

This conception of vowel articulation has been known to be inaccurate since 1928. Peter Ladefoged has said that "early phoneticians... thought they were describing the highest point of the tongue, but they were not. They were actually describing formant frequencies."<ref>Ladefoged & Disner (2012) ''Vowels and Consonants'', 3rd ed., p. 132.</ref> (See below.) The IPA ''Handbook'' concedes that "the vowel quadrilateral must be regarded as an abstraction and not a direct mapping of tongue position."<ref>IPA (1999) ''Handbook of the IPA'', p. 12.</ref>

Nonetheless, the concept that vowel qualities are determined primarily by tongue position and lip rounding continues to be used in pedagogy, as it provides an intuitive explanation of how vowels are distinguished.

===Height===<!-- This section is linked from [[Latin spelling and pronunciation]] -->
Theoretically, vowel height refers to the vertical position of either the tongue or the jaw (depending on the model) relative to either the roof of the mouth or the aperture of the [[jaw]]. In practice, however, it refers to the first [[formant]] (lowest resonance of the voice), abbreviated F1, which is associated with the height of the tongue. There are two terms commonly applied to refer to two degrees of vowel height: in '''close vowels''', also known as '''high vowels''', such as {{IPA|[i]}} and {{IPA|[u]}}, the first formant is consistent with the tongue being positioned close to the palate, high in the mouth, whereas in '''open vowels''', also known as '''low vowels''', such as {{IPA|[a]}}, F1 is consistent with the jaw being open and the tongue being positioned low in the mouth. Height is defined by the inverse of the F1 value: the higher the frequency of the first formant, the lower (more open) the vowel.{{efn|According to [[Peter Ladefoged]], traditional articulatory descriptions such as height and backness "are not entirely satisfactory", and when phoneticians describe a vowel as high or low, they are in fact describing an acoustic quality rather than the actual position of the tongue.<ref>Ladefoged, Peter (2006) ''A Course in Phonetics (Fifth Edition)'', Boston, MA: Thomson Wadsworth, p. 189.</ref>}} In [[John Esling]]'s usage, where [[front vowel|fronted vowels]] are distinguished in height by the position of the jaw rather than the tongue, only the terms 'open' and 'close' are used, as 'high' and 'low' refer to the position of the tongue.

The [[International Phonetic Alphabet]] has letters for six degrees of vowel height for full vowels (plus the reduced mid vowel {{IPA|[ə]}}), but it is extremely unusual for a language to distinguish this many degrees without other attributes. The IPA letters distinguish (sorted according to height, with the top-most one being the highest and the bottom-most being the lowest):

* [[close vowel|close]] ({{aka}} high): i y ɨ ʉ ɯ u
* [[near-close vowel|near-close]] ({{aka}} near-high): ɪ ʏ ʊ
* [[close-mid vowel|close-mid]] ({{aka}} high-mid): e ø ɘ ɵ ɤ o
* [[mid vowel|mid]]: (the reduced vowel {{IPA|[ə]}})
* [[open-mid vowel|open-mid]] ({{aka}} low-mid): ɛ œ ɜ ɞ ʌ ɔ
* [[near-open vowel|near-open]] ({{aka}} near-low): æ (plus the reduced vowel {{IPA|[ɐ]}})
* [[open vowel|open]] ({{aka}} low): a ɶ ɑ ɒ

The letters {{angbr IPA|e, ø, ɘ, ɵ, ɤ, o}} are defined as close-mid but are commonly used for true [[mid vowel]]s. If more precision is required, true mid vowels may be written with a lowering or raising diacritic: {{angbr IPA|e̞, ɘ̞, ø̞, ɵ̞, ɤ̞, o̞}} or {{angbr IPA|ɛ̝ œ̝ ɜ̝ ɞ̝ ʌ̝ ɔ̝}}.

The [[Kensiu language]], spoken in Malaysia and Thailand, is highly unusual in contrasting true mid vowels with both close-mid and open-mid vowels, without any additional parameters such as length, roundness or ATR. The front vowels, {{IPA|/i ɪ e e̞ ɛ/}}, along with open {{IPA|/a/}}, make a six-way height distinction; this holds even for the nasal vowels. A few varieties of [[German language|German]] have been reported to have five contrastive vowel heights that are independent of length or other parameters. For example, the [[Austro-Bavarian|Bavarian]] dialect of [[Amstetten, Lower Austria|Amstetten]] has thirteen long vowels, which have been analyzed as four vowel heights (close, close-mid, mid, open-mid) each among the front unrounded, front rounded, and back rounded vowels, along with an open vowel for a fifth height: {{IPA|/i e ɛ̝ ɛ/, /y ø œ̝ œ/, /u o ɔ̝ ɔ/, /a/}}. Apart from the aforementioned [[Kensiu language]], no other language is known to contrast more than four degrees of vowel height.

The parameter of vowel height appears to be the primary cross-linguistic feature of vowels in that all [[spoken language]]s that have been researched till now use height as a contrastive feature. No other parameter, even backness or rounding (see below), is used in all languages. Some languages have [[vertical vowel system]]s in which at least at a phonemic level, only height is used to distinguish vowels.

=== Backness ===
[[File:Cardinal vowel tongue position-front.svg|thumb|upright=0.9|Idealistic tongue positions of [[Cardinal vowel|cardinal]] front vowels with highest point indicated]]
Vowel backness is named for the position of the tongue during the articulation of a vowel relative to the back of the mouth. As with vowel height, however, it is ''defined'' by a formant of the voice, in this case the second, F2, not by the position of the tongue. In front vowels, such as {{IPA|[i]}}, the frequency of F2 is relatively high, which generally corresponds to a position of the tongue forward in the mouth, whereas in back vowels, such as {{IPA|[u]}}, F2 is low, consistent with the tongue being positioned towards the back of the mouth.

The [[International Phonetic Alphabet]] defines five degrees of vowel backness (sorted according to backness, with the top-most one being the front-most back and the bottom-most being the back-most):
* [[front vowel|front]]
* [[near-front vowel|near-front]]
* [[central vowel|central]]
* [[near-back vowel|near-back]]
* [[back vowel|back]]

To them may be added front-central and back-central, corresponding to the vertical lines separating central from front and back vowel spaces in several IPA diagrams. However, ''front-central'' and ''back-central'' may also be used as terms synonymous with ''near-front'' and ''near-back''. No language is known to contrast more than three degrees of backness nor is there a language that contrasts front with near-front vowels nor back with near-back ones.

Although some English dialects have vowels at five degrees of backness, there is no known language that distinguishes five degrees of backness without additional differences in height or rounding.

=== Roundedness ===
{{Main|Roundedness}}
[[Roundedness]] is named after the rounding of the lips in some vowels. Because lip rounding is easily visible, vowels may be commonly identified as rounded based on the articulation of the lips. Acoustically, rounded vowels are identified chiefly by a decrease in F2, although F1 is also slightly decreased.

In most languages, roundedness is a reinforcing feature of mid to high back vowels rather than a distinctive feature. Usually, the higher a back vowel, the more intense is the rounding. However, in some languages, roundedness is independent from backness, such as French and German (with front rounded vowels), most [[Uralic languages]] ([[Estonian language|Estonian]] has a rounding contrast for {{IPA|/o/}} and front vowels), [[Turkic languages]] (with a rounding distinction for front vowels and {{IPA|/u/}}), and [[Vietnamese language|Vietnamese]] with back unrounded vowels.

Nonetheless, even in those languages there is usually some phonetic correlation between rounding and backness: front rounded vowels tend to be more front-central than front, and back unrounded vowels tend to be more back-central than back. Thus, the placement of unrounded vowels to the left of rounded vowels on the IPA vowel chart is reflective of their position in formant space.

Different kinds of [[labialization]] are possible. In mid to high rounded back vowels the lips are generally protruded ("pursed") outward, a phenomenon known as ''endolabial rounding'' because the insides of the lips are visible, whereas in mid to high rounded front vowels the lips are generally "compressed" with the margins of the lips pulled in and drawn towards each other, a phenomenon known as ''exolabial rounding.'' However, not all languages follow that pattern. [[Japanese language|Japanese]] {{IPA|/u/}}, for example, is an exolabial (compressed) back vowel, and sounds quite different from an English endolabial {{IPA|/u/}}. [[Swedish language|Swedish]] and [[Norwegian language|Norwegian]] are the only two known languages in which the feature is contrastive; they have both exo- and endo-labial [[close front rounded vowel|close front vowels]] and [[close central rounded vowel|close central vowels]], respectively. In many phonetic treatments, both are considered types of rounding, but some phoneticians do not believe that these are subsets of a single phenomenon and posit instead three independent features of ''rounded'' (endolabial), ''compressed'' (exolabial), and unrounded. The lip position of unrounded vowels may also be classified separately as ''spread'' and ''neutral'' (neither rounded nor spread).<ref>IPA (1999), p. 13.</ref> Others distinguish compressed rounded vowels, in which the corners of the mouth are drawn together, from compressed unrounded vowels, in which the lips are compressed but the corners remain apart as in spread vowels.

===Front, raised and retracted===
[[File:Esling vowel chart.png|thumb|Front, raised and retracted are the three articulatory dimensions of vowel space. Open and close refer to the jaw, not the tongue.]]
The conception of the tongue moving in two directions, high&ndash;low and front&ndash;back, is not supported by articulatory evidence and does not clarify how articulation affects vowel quality. Vowels may instead be characterized by the three directions of movement of the tongue from its neutral position: front (forward), raised (upward and back), and retracted (downward and back). Front vowels ({{IPA|[i, e, ɛ]}} and, to a lesser extent {{IPA|[ɨ, ɘ, ɜ, æ]}}, etc.), can be secondarily qualified as close or open, as in the traditional conception, but this refers to jaw rather than tongue position. In addition, rather than there being a unitary category of back vowels, the regrouping posits [[raised vowel]]s, where the body of the tongue approaches the velum ({{IPA|[u, o, ɨ}}], etc.), and [[retracted vowel]]s, where the root of the tongue approaches the pharynx ({{IPA|[ɑ, ɔ]}}, etc.):
* [[Front vowel#Articulatorily fronted vowels|front]]
* [[Raised vowel|raised]]
* [[Retracted vowel|retracted]]

Membership in these categories is scalar, with the mid-central vowels being marginal to any category.<ref>John Esling (2005) "There Are No Back Vowels: The Laryngeal Articulator Model", ''The Canadian Journal of Linguistics'' 50:&nbsp;13–44</ref>

=== Nasalization ===
{{Main|Nasal vowel|Nasalization}}
[[Nasalization]] occurs when air escapes through the nose. Vowels are often nasalised under the influence of neighbouring nasal consonants, as in [[English language|English]] ''hand'' {{IPA|[hæ̃nd]}}. ''Nasalised vowels'', however, should not be confused with ''nasal vowels''. The latter refers to vowels that are distinct from their oral counterparts, as in [[French language|French]] {{IPA|/ɑ/}} vs. {{IPA|/ɑ̃/}}.<ref>{{cite web |title=Nasals and Nasalization |url=https://www.oxfordbibliographies.com/view/document/obo-9780199772810/obo-9780199772810-0205.xml |website=Oxford Bibliographies |publisher=Oxford |access-date=27 June 2017 |ref=10.1093/OBO/9780199772810-0205 |first1=Bert |last1=Botma |date=8 December 2020 }}</ref>

In [[nasal vowel]]s, the [[soft palate|velum]] is lowered, and some air travels through the nasal cavity as well as the mouth. An oral vowel is a vowel in which all air escapes through the mouth. [[Polish language|Polish]] and [[Portuguese language|Portuguese]] also contrast nasal and oral vowels.

=== Phonation ===
{{Main|Phonation}}
[[Phonation|Voicing]] describes whether the [[vocal cords]] are vibrating during the articulation of a vowel. Most languages have only voiced vowels, but several [[Native American languages]], such as [[Cheyenne language|Cheyenne]] and [[Totonac language|Totonac]], have both voiced and devoiced vowels in complementary distribution. Vowels are devoiced in whispered speech. In Japanese and in [[Quebec French]], vowels that are between voiceless consonants are often devoiced. [[Keres language|Keres]] is disputed to have phonemic voiceless vowels but no language is confirmed to have them phonemically.

[[Modal voice]], [[creaky voice]], and [[breathy voice]] (murmured vowels) are [[phonation]] types that are used contrastively in some languages. Often, they co-occur with [[tone (linguistics)|tone]] or stress distinctions; in the [[Mon language]], vowels pronounced in the high tone are also produced with creaky voice. In such cases, it can be unclear whether it is the tone, the voicing type, or the pairing of the two that is being used for [[phonemic contrast]]. The combination of phonetic cues (phonation, tone, stress) is known as ''register'' or ''register complex''.

=== Tenseness ===
{{Main|Tenseness|Checked and free vowels}}
[[Tenseness]] is used to describe the opposition of ''tense vowels'' vs. ''lax vowels''. This opposition has traditionally been thought to be a result of greater muscular tension, though phonetic experiments have repeatedly failed to show this.{{citation needed|date=April 2019}}

Unlike the other features of vowel quality, tenseness is only applicable to the few languages that have this opposition (mainly [[Germanic language]]s, e.g. [[German language|German]]), whereas the vowels of the other languages (e.g. [[Spanish language|Spanish]]) cannot be described with respect to tenseness in any meaningful way.{{citation needed|date=April 2019}}

One may distinguish the English tense vs. lax vowels roughly, with its spelling. Tense vowels usually occur in words with the final [[silent e|silent {{vr|e}}]], as in ''mate''. Lax vowels occur in words without the silent {{vr|e}}, such as ''mat''. In [[American English]], lax vowels {{IPA|[ɪ, ʊ, ɛ, ʌ, æ]}} do not appear in stressed open syllables.<ref>[[Peter Ladefoged|Ladefoged, Peter]] & Johnson, Keith. (2011). Tense and Lax Vowels. In ''A Course in Phonetics'' (6th ed., pp. 98–100). Boston, MA: Cengage.</ref>

In traditional grammar, ''long vowels'' vs. ''short vowels'' are more commonly used, compared to ''tense'' and ''lax''. The two sets of terms are used interchangeably by some because the features are concomitant in some varieties of English.{{clarify|date=April 2019}} In most [[Germanic languages]], lax vowels can only occur in [[Syllable#Open and closed|closed syllables]]. Therefore, they are also known as ''checked vowels'', whereas the tense vowels are called ''free vowels'' since they can occur in any kind of syllable.{{citation needed|date=April 2019}}

=== Tongue root position ===
{{Main|Advanced and retracted tongue root|Vowel harmony}}
Advanced tongue root (ATR) is a feature common across much of Africa, the [[Pacific Northwest]], and scattered other languages such as Modern [[Mongolian language|Mongolian]].<ref>{{Cite thesis |title=Towards a phonetic and phonological typology of post-velar articulation |url=https://open.library.ubc.ca/soa/cIRcle/collections/ubctheses/831/items/1.0086353 |publisher=University of British Columbia |date=1993 |first=Nicola J. |last=Bessell}}</ref> The contrast between advanced and retracted tongue root resembles the tense-lax contrast acoustically, but they are articulated differently. Those vowels involve noticeable tension in the vocal tract.

=== Secondary narrowings in the vocal tract ===
{{Main|Pharyngealization}}
[[Pharyngealisation|Pharyngealized vowels]] occur in some languages like [[Sedang language|Sedang]] and the [[Tungusic languages]]. Pharyngealisation is similar in articulation to retracted tongue root but is [[acoustics|acoustically]] distinct.

A stronger degree of pharyngealisation occurs in the [[Northeast Caucasian languages]] and the [[Khoisan languages]]. They might be called '''epiglottalized''' since the primary constriction is at the tip of the epiglottis.

The greatest degree of pharyngealisation is found in the '''[[strident vowel]]s''' of the Khoisan languages, where the [[larynx]] is raised, and the pharynx constricted, so that either the epiglottis or the [[arytenoid cartilage]]s vibrate instead of the vocal cords.

The terms ''pharyngealized'', ''epiglottalized'', ''strident'', and ''sphincteric'' are sometimes used interchangeably.

==== Rhotic vowels ====
{{Main|R-colored vowel}}
[[R-colored vowel|Rhotic vowels]] are the "R-colored vowels" of American English and a few other languages.

=== Reduced vowels ===
{{main|Vowel reduction}}
{| class="wikitable floatright" style="text-align:center"
|+Common reduced vowels<br><small>(IPA provides only {{angbr IPA|ə}} and {{angbr IPA|ɐ}})</small>
|- class="small"
! 
! <small>[[Near-front vowel|Near-<br>front]]</small>
! colspan=2| <small>[[Central vowel|Central]]</small>
! <small>[[Near-back vowel|Near-<br>back]]</small>
|-
! <small>[[Near-close vowel|Near-close]]</small>
|colspan=2| {{IPA|ᵻ}}
|colspan=2| {{IPA|ᵿ}}
|-
! <small>[[Mid vowel|Mid]]</small>
|
|colspan=2| {{IPA|ə}}
|
|-
! <small>[[Near-open vowel|Near-open]]</small>
| 
|colspan=2| {{IPA|ɐ}}
|
|}

Some languages, such as English and Russian, have what are called 'reduced', 'weak' or 'obscure' vowels in some unstressed positions. These do not correspond one-to-one with the vowel sounds that occur in stressed position (so-called 'full' vowels), and they tend to be mid-centralized in comparison, as well as having reduced rounding or spreading. The IPA has long provided two letters for obscure vowels, mid {{angbr IPA|ə}} and lower {{angbr IPA|ɐ}}, neither of which are defined for rounding. Dialects of English may have up to four phonemic reduced vowels: {{IPA|/ɐ/}}, {{IPA|/ə/}}, and higher unrounded {{IPA|/ᵻ/}} and rounded {{IPA|/ᵿ/}}. (The non-IPA letters {{angbr IPA|ᵻ}} and {{angbr IPA|ᵿ}} may be used for the latter to avoid confusion with the clearly defined values of IPA letters like {{angbr IPA|ɨ}} and {{angbr IPA|ɵ}}, which are also seen, since the IPA only provides for two reduced vowels.)

== Acoustics ==
{{hatnote|Related article: [[Phonetics]]}}
[[File:Spectrogram -iua-.png|thumb|upright=1.8|Spectrogram of vowels {{IPA|[i, u, ɑ]|cat=no}}. {{IPA|[ɑ]}} is a low vowel, so its F1 value is higher than that of {{IPA|[i]}} and {{IPA|[u]}}, which are high vowels. {{IPA|[i]}} is a front vowel, so its F2 is substantially higher than that of {{IPA|[u]}} and {{IPA|[ɑ]}}, which are back vowels.]]
{{multiple image
| align = right
| direction = vertical
| image1 = Vowel triange, cardinal vowels.png
| caption1 = An idealized schematic of vowel space, based on the formants of [[Daniel Jones (phonetician)|Daniel Jones]] and [[John C. Wells|John Wells]] pronouncing the cardinal vowels of the IPA. The scale is logarithmic. The grey range is where F2 would be less than F1, which by definition is impossible. {{IPA|[a]}} is an extra-low central vowel. Phonemically it may be front or back, depending on the language. Rounded vowels that are front in tongue position are front-central in formant space, while unrounded vowels that are back in articulation are back-central in formant space. Thus {{IPA|[y ɯ]}} have perhaps similar F1 and F2 values to the high central vowels {{IPA|[ɨ ʉ]}}, being distinguished by rounding (F3); similarly {{IPA|[ø ɤ]}} vs central {{IPA|[ɘ ɵ]}} and {{IPA|[œ ʌ]}} vs central {{IPA|[ɜ ɞ]}}.
| image2 = Vowel triangle, intermediate vowels.png
| caption2 = The same chart, with a few intermediate vowels. Low front {{IPA|[æ]}} is intermediate between {{IPA|[a]}} and {{IPA|[ɛ]}}, while {{IPA|[ɒ]}} is intermediate between {{IPA|[ɑ]}} and {{IPA|[ɔ]}}. The back vowels change gradually in rounding, from unrounded {{IPA|[ɑ]}} and slightly rounded {{IPA|[ɒ]}} to tightly rounded {{IPA|[u]}}; similarly slightly rounded {{IPA|[œ]}} to tightly rounded {{IPA|[y]}}. With {{IPA|[a]}} seen as an (extra-)low central vowel, the vowels {{IPA|[æ ɐ ɑ]}} can be redefined as front, central and back (near-)low vowels.
}}

The acoustics of vowels are fairly well understood. The different vowel qualities are realized in acoustic analyses of vowels by the relative values of the [[formant]]s, acoustic [[resonance]]s of the vocal tract which show up as dark bands on a [[spectrogram]]. The vocal tract acts as a [[resonant cavity]], and the position of the jaw, lips, and tongue affect the parameters of the resonant cavity, resulting in different formant values. The acoustics of vowels can be visualized using spectrograms, which display the acoustic energy at each frequency, and how this changes with time.

The first formant, abbreviated "F1", corresponds to vowel openness (vowel height). [[Open vowel]]s have high F1 frequencies, while [[close vowel]]s have low F1 frequencies, as can be seen in the accompanying spectrogram: The {{IPA|[i]}} and {{IPA|[u]}} have similar low first formants, whereas {{IPA|[ɑ]}} has a higher formant.

The second formant, F2, corresponds to vowel frontness. [[Back vowel]]s have low F2 frequencies, while [[front vowel]]s have high F2 frequencies. This is very clear in the spectrogram, where the front vowel {{IPA|[i]}} has a much higher F2 frequency than the other two vowels. However, in open vowels, the high F1 frequency forces a rise in the F2 frequency as well, so an alternative measure of frontness is the ''difference'' between the first and second formants. For this reason, some people prefer to plot as F1 vs. F2&nbsp;–&nbsp;F1. (This dimension is usually called 'backness' rather than 'frontness', but the term 'backness' can be counterintuitive when discussing formants.)

In the third edition of his textbook, [[Peter Ladefoged]] recommended using plots of F1 against F2&nbsp;–&nbsp;F1 to represent vowel quality.<ref>Ladefoged, Peter (1993) ''A Course in Phonetics (Third Edition)'', Fort Worth: Harcourt Brace Jovanovich, p. 197.</ref> However, in the fourth edition, he changed to adopt a simple plot of F1 against F2,<ref>Ladefoged, Peter (2001) ''A Course in Phonetics (Fourth Edition)'', Fort Worth: Harcourt, p. 177.</ref> and this simple plot of F1 against F2 was maintained for the fifth (and final) edition of the book.<ref>Ladefoged, Peter (2006) ''A Course in Phonetics (Fifth Edition)'', Boston: Thomson Wadsworth, p. 189.</ref> Katrina Hayward compares the two types of plots and concludes that plotting of F1 against F2&nbsp;–&nbsp;F1 "is not very satisfactory because of its effect on the placing of the central vowels",<ref>Hayward, Katrina (2000) ''Experimental Phonetics'', Harlow, UK: Pearson, p. 160.</ref> so she also recommends use of a simple plot of F1 against F2. In fact, this kind of plot of F1 against F2 has been used by analysts to show the quality of the vowels in a wide range of languages, including RP,<ref>{{Cite journal | doi = 10.1017/S0025100300005417 | author = Deterding, David | year = 1997 | title = The formants of monophthong vowels in Standard Southern British English Pronunciation | journal = Journal of the International Phonetic Association | volume = 27 | issue = 1–2| pages = 47–55 | s2cid = 146157247 }}</ref><ref>{{Cite journal | doi = 10.1017/S0025100305002124 | author = Hawkins, Sarah and Jonathan Midgley | year = 2005 | title = Formant frequencies of RP monophthongs in four age groups of speakers | journal = Journal of the International Phonetic Association | volume = 35 | issue = 2| pages = 183–199 | s2cid = 53532910 }}</ref> the Queen's English,<ref>Harrington, Jonathan, Sallyanne Palethorpe and Catherine Watson (2005) Deepening or lessening the divide between diphthongs: an analysis of the Queen's annual Christmas broadcasts. In William J. Hardcastle and Janet Mackenzie Beck (eds.) '' A Figure of Speech: A Festschrift for John Laver'', Mahwah, NJ: Lawrence Erlbaum, pp. 227-261.</ref> American English,<ref>{{Cite journal | doi = 10.1017/S0025100306002817 | author = Flemming, Edward and Stephanie Johnson | year = 2007 | title = Rosa's roses: reduced vowels in American English | url = http://web.mit.edu/flemming/www/paper/reduced-rev2.pdf| journal = Journal of the International Phonetic Association | volume = 37 | pages = 83–96 | citeseerx = 10.1.1.536.1989 | s2cid = 145535175 }}</ref> Singapore English,<ref>{{Cite journal | doi = 10.1075/eww.24.1.02det | author = Deterding, David | year = 2003 | title = An instrumental study of the monophthong vowels of Singapore English | journal = English World-Wide | volume = 24 | pages = 1–16 }}</ref> Brunei English,<ref>{{Cite journal | doi = 10.1075/eww.27.3.03sha | author = Salbrina, Sharbawi | year = 2006 | title = The vowels of Brunei English: an acoustic investigation | journal = English World-Wide | volume = 27 | issue = 3| pages = 247–264 }}</ref> North Frisian,<ref>{{Cite journal | doi = 10.1017/S002510030400180X |author1-link=Ocke-Schwen Bohn | author = Bohn, Ocke-Schwen | year = 2004 | title = How to organize a fairly large vowel inventory: the vowels of Fering (North Frisian) | url = http://pure.au.dk/portal/files/44857633/jipa34.pdf | journal = Journal of the International Phonetic Association | volume = 34 | issue = 2| pages = 161–173 | s2cid = 59404078 }}</ref> Turkish Kabardian,<ref>{{Cite journal | doi = 10.1017/S0025100306002532 | author = Gordon, Matthew and Ayla Applebaum | year = 2006 | title = Phonetic structures of Turkish Kabardian | url = http://www.linguistics.ucsb.edu/faculty/gordon/kabardianphonetics.pdf| journal = Journal of the International Phonetic Association | volume = 36 | issue = 2| pages = 159–186 | citeseerx = 10.1.1.233.1206 | s2cid = 6665600 }}</ref> and various indigenous Australian languages.<ref>Fletcher, Janet (2006) Exploring the phonetics of spoken narratives in Australian indigenous languages. In William J. Hardcastle and Janet Mackenzie Beck (eds.) '' A Figure of Speech: A Festschrift for John Laver'', Mahwah, NJ: Lawrence Erlbaum, pp. 201–226.</ref>

[[R-colored vowel]]s are characterized by lowered F3 values.

Rounding is generally realized by a decrease of F2 that tends to reinforce vowel backness. One effect of this is that back vowels are most commonly rounded while front vowels are most commonly unrounded; another is that rounded vowels tend to plot to the right of unrounded vowels in vowel charts. That is, there is a reason for plotting vowel pairs the way they are.

== Prosody and intonation ==
{{Main|Prosody (linguistics)|Intonation (linguistics)|Vowel length | l1=Prosody|l2=Intonation}}
In addition to variation in vowel quality as described above, vowels vary as a result of differences in [[prosody (linguistics)|prosody]]. The most important prosodic variables are [[pitch (music)|pitch]] ([[fundamental frequency]]), [[loudness]] ([[sound intensity|intensity]]) and [[vowel length|length]] ([[length (phonetics)|duration]]). However, the features of prosody are usually considered to apply not to the vowel itself, but to the [[syllable]] in which the vowel occurs. In other words, the ''domain'' of prosody is the syllable, not the segment (vowel or consonant).<ref>Lehiste, Ilse, ''Suprasegmentals'', M.I.T 1970, pp. 42, 84, 147</ref> We can list briefly the effect of prosody on the vowel component of a syllable.

* Pitch: in the case of a syllable such as 'cat', the only [[Voicing (phonetics)|voiced]] portion of the syllable is the vowel, so the vowel carries the pitch information. This may relate to the syllable in which it occurs, or to a larger stretch of speech to which an intonation contour belongs. In a word such as 'man', all the segments in the syllable are [[sonorant]] and all will participate in any pitch variation.
* Loudness: this variable has been traditionally associated with linguistic [[stress (linguistics)|stress]], though other factors are usually involved in this. Lehiste (ibid) argues that stress, or loudness, could not be associated with a single segment in a syllable independently of the rest of the syllable (p.&nbsp;147). This means that vowel loudness is a concomitant of the loudness of the syllable in which it occurs.
* Length: it is important to distinguish two aspects of [[vowel length]]. One is the [[phonology|phonological]] difference in length exhibited by some languages. [[Japanese language|Japanese]], [[Finnish language|Finnish]], [[Hungarian language|Hungarian]], [[Arabic language|Arabic]] and [[Latin]] have a two-way phonemic contrast between [[vowel length|short and long vowels]]. The [[Mixe language]] has a three-way contrast among short, half-long, and long vowels.<ref>Ladefoged, P. and Maddieson, I. ''The Sounds of the World's Languages'', Blackwell (1996), p 320</ref> The other type of length variation in vowels is non-distinctive, and is the result of prosodic variation in speech: vowels tend to be lengthened when in a stressed syllable, or when utterance rate is slow.

== Monophthongs, diphthongs, triphthongs ==
{{Main|Monophthong|Diphthong|Triphthong|Semivowel}}
A vowel sound whose quality does not change throughout the vowel is called a [[monophthong]]. Monophthongs are sometimes called "pure" or "stable" vowels. A vowel sound that glides from one quality to another is called a [[diphthong]], and a vowel sound that glides successively through three qualities is a [[triphthong]].

All languages have monophthongs and many languages have diphthongs, but triphthongs or vowel sounds with even more target qualities are relatively rare cross-linguistically. English has all three types: the vowel sound in ''hit'' is a monophthong {{IPA|/ɪ/}}, the vowel sound in ''boy'' is in most dialects a diphthong {{IPA|/ɔɪ/}}, and the vowel sounds of ''flower'', {{IPA|/aʊər/}}, form a triphthong or disyllable, depending on the dialect.

In [[phonology]], diphthongs and triphthongs are distinguished from sequences of monophthongs by whether the vowel sound may be analyzed into distinct [[phonemes]]. For example, the vowel sounds in a two-syllable pronunciation of the word ''flower'' ({{IPA|/ˈflaʊər/}}) phonetically form a disyllabic triphthong but are phonologically a sequence of a diphthong (represented by the letters {{angle bracket|ow}}) and a monophthong (represented by the letters {{angle bracket|er}}). Some linguists use the terms ''diphthong'' and ''triphthong'' only in this phonemic sense.

== Written vowels ==
{{Main|Writing system}}
The name "vowel" is often used for the symbols that represent vowel sounds in a language's [[writing system]], particularly if the language uses an [[alphabet]]. In writing systems based on the [[Latin alphabet]], the letters {{vr|a}}, {{vr|e}}, {{vr|i}}, {{vr|o}}, {{vr|u}}, {{vr|y}}, {{vr|w}} and sometimes others can all be used to represent vowels. However, not all of these letters represent the vowels in all languages that use this writing, or even consistently within one language. Some of them, especially {{vr|w}} and {{vr|y}}, are also used to represent [[approximant consonant]]s. Moreover, a vowel might be represented by a letter usually reserved for consonants, or a combination of letters, particularly where one letter represents several sounds at once, or vice versa; examples from English include {{vr|igh}} in "thigh" and {{vr|x}} in "x-ray". In addition, extensions of the Latin alphabet have such independent vowel letters as {{vr|ą}}, {{vr|ę}}, {{vr|į}}, {{vr|ǫ}}, and {{vr|ų}}.

The phonetic values vary considerably by language, and some languages use {{vr|i}} and {{vr|y}} for the consonant {{IPA|[j]}}, e.g., initial {{vr|i}} in [[Italian language|Italian]] or [[Romanian language|Romanian]] and initial {{vr|y}} in English. In the original Latin alphabet, there was no written distinction between {{vr|v}} and {{vr|u}}, and the letter represented the approximant {{IPA|[w]}} and the vowels {{IPA|[u]}} and {{IPA|[ʊ]}}. In Modern [[Welsh language|Welsh]], {{vr|w}} represents these same sounds. There is not necessarily a direct one-to-one correspondence between the vowel sounds of a language and the vowel letters. Many languages that use a form of the Latin alphabet have more vowel sounds than can be represented by the standard set of five vowel letters. In English spelling, the five letters {{vr|a}} {{vr|e}} {{vr|i}} {{vr|o}} and {{vr|u}} can represent a variety of vowel sounds, while the letter {{vr|y}} frequently represents vowels (as in e.g., "g'''y'''m", "happ'''y'''", or the diphthongs in "cr'''y'''", "th'''y'''me");<ref>In [[Wyvern|wyrm]] and [[myrrh]], there is neither a vowel letter nor, in rhotic dialects, a vowel sound.</ref> {{vr|w}} is used in representing some [[diphthong]]s (as in "co'''w'''") and to represent a [[monophthong]] in the borrowed words "{{linktext|cwm}}" and "{{linktext|crwth}}" (sometimes ''cruth'').

Other languages cope with the limitation in the number of Latin vowel letters in similar ways. Many languages make extensive use of combinations of letters to represent various sounds. Other languages use vowel letters with modifications, such as {{vr|ä}} in [[Swedish language|Swedish]], or add [[diacritic]]al marks, like [[Ogonek|ogoneks]], to vowels to represent the variety of possible vowel sounds. Some languages have also constructed additional vowel letters by modifying the standard Latin vowels in other ways, such as {{vr|æ}} or {{vr|ø}} that are found in some of the [[Scandinavian language]]s. The [[International Phonetic Alphabet]] has a set of 28 symbols representing the range of essential vowel qualities, and a further set of diacritics to denote variations from the basic vowel.

The writing systems used for some languages, such as the [[Hebrew alphabet]] and the [[Arabic alphabet]], do not ordinarily mark all the vowels, since they are frequently unnecessary in identifying a word. {{citation needed|date=October 2015}} Technically, these are called [[abjad]]s rather than alphabets. Although it is possible to construct English sentences that can be understood without written vowels (<span title="Can you read this?">''cn y rd ths?''</span>), single words in English lacking written vowels can be indistinguishable; consider ''dd'', which could be any of ''dad, dada, dado, dead, deed, did, died, diode, dodo, dud, dude, odd, add'', and ''aided''. (Abjads generally express some word-internal vowels and all word-initial and word-final vowels, whereby the ambiguity will be much reduced.) The [[Masoretes]] devised a [[niqqud|vowel notation system]] for Hebrew [[Jewish scripture]] that is still widely used, as well as the [[trope (music)|trope]] symbols used for its [[Hebrew cantillation|cantillation]]; both are part of [[Oral Torah|oral tradition]] and still the basis for many bible translations—Jewish and Christian.

===Shifts===
The differences in pronunciation of vowel letters between English and its related languages can be accounted for by the [[Great Vowel Shift]]. After printing was introduced to England, and therefore after spelling was more or less standardized, a series of dramatic changes in the pronunciation of the vowel phonemes occurred, and continued into recent centuries, but were not reflected in the spelling system. This has led to numerous inconsistencies in the spelling of English vowel sounds and the pronunciation of English vowel letters (and to the mispronunciation of foreign words and names by speakers of English).

==Audio samples==
{{IPA vowels|audio=yes}}

== Systems ==
The importance of vowels in distinguishing one word from another varies from language to language. Nearly all languages have at least three phonemic vowels, usually {{IPA|/i/, /a/, /u/}} as in [[Classical Arabic]], some [[Malayic languages]] of Borneo (including [[Banjarese language|Banjarese]]) and [[Inuktitut language|Inuktitut]], though [[Adyghe language|Adyghe]] and many [[Sepik languages]] have a [[vertical vowel system]] of {{IPA|/ɨ/, /ə/, /a/}}. Very few languages have fewer, though some [[Arrernte language|Arrernte]], [[Northwest Caucasian languages|Circassian]], and [[Ndu languages]] have been argued to have just two, {{IPA|/ə/}} and {{IPA|/a/}}, with {{IPA|[ɨ]}} being [[epenthesis|epenthetic]].

It is not straightforward to say which language has the most vowels, since that depends on how they are counted. For example, long vowels, nasal vowels, and various [[phonation]]s may or may not be counted separately; indeed, it may sometimes be unclear if phonation belongs to the vowels or the consonants of a language. If such things are ignored and only vowels with dedicated IPA letters ('vowel qualities') are considered, then very few languages have more than ten. The [[Germanic languages]] have some of the largest inventories: [[Danish phonology|Standard Danish]] has 11 to 13 short vowels ({{IPA|/(a), ɑ, (ɐ), e, ə, ɛ, i, o, ɔ, u, ø, œ, y/}}), while the [[Amstetten (district)|Amstetten]] dialect of [[Bavarian German|Bavarian]] has been reported to have thirteen long vowels: {{IPA|/i, y, e, ø, ɛ, œ, æ, ɶ, a, ɒ, ɔ, o, u/}}.{{Citation needed|date=May 2010}} The situation can be quite disparate within a same family language: [[Spanish language|Spanish]] and [[French language|French]] are two closely related [[Romance languages]] but Spanish has only five pure vowel qualities, {{IPA|/a, e, i, o, u/}}, while classical French has eleven: {{IPA|/a, ɑ, e, ɛ, i, o, ɔ, u, y, œ, ø/}} and four nasal vowels {{IPA|/ɑ̃/, /ɛ̃/, /ɔ̃/ and /œ̃/}}. The [[Mon–Khmer languages]] of Southeast Asia also have some large inventories, such as the ten vowels of [[Khmer language|Khmer]]: {{IPA|/i, ɨ, e, ɛ, a, ɑ, ɔ, o, u, ə/}}. [[Wu Chinese|Wu]] dialects have the largest inventories of Chinese; the [[Jinhui dialect]] of Wu has also been reported to have eleven vowels: ten basic vowels, {{IPA|/i, y, e, ø, ɛ, ɑ, ɔ, o, u, ɯ/}}, plus restricted {{IPA|/ɨ/}}; this does not count the seven nasal vowels.<!--An earlier link had {{IPA|/i y e ø æ a ɑ ɯ u ɵ ɒ ɐ/}}, plus restricted {{IPA|/ɿ/}}, and allophones {{IPA|[ʌ ɛ ə ɤ ɪ ɔ o œ ʏ]}}, which differs from the current link.--><ref>[http://comonca.org.cn/lh/Doc/D13.pdf Values in open oral syllables] {{webarchive|url=https://web.archive.org/web/20110726061849/http://comonca.org.cn/lh/Doc/D13.pdf |date=2011-07-26 }}</ref>

One of the most common vowels is {{IPA|[a̠]}}; it is nearly universal for a language to have at least one open vowel, though most dialects of English have an {{IPA|[æ]}} and a {{IPA|[ɑ]}}—and often an {{IPA|[ɒ]}}, all open vowels—but no central {{IPA|[a]}}. Some [[Tagalog phonology|Tagalog]] and [[Cebuano language|Cebuano]] speakers have {{IPA|[ɐ]}} rather than {{IPA|[a]}}, and [[Yolŋu Matha|Dhangu Yolngu]] is described as having {{IPA|/ɪ ɐ ʊ/}}, without any peripheral vowels. {{IPA|[i]}} is also extremely common, though [[Tehuelche language|Tehuelche]] has just the vowels {{IPA|/e a o/}} with no close vowels. The third vowel of the Arabic-type three-vowel system, {{IPA|/u/}}, is considerably less common. A large fraction of the languages of North America happen to have a four-vowel system without {{IPA|/u/}}: {{IPA|/i, e, a, o/}}; [[Nahuatl language|Nahuatl]] and [[Navajo language|Navajo]] are examples.

In most languages, vowels serve mainly to distinguish separate [[lexeme]]s, rather than different inflectional forms of the same lexeme as they commonly do in the Semitic languages. For example, while English ''man'' becomes ''men'' in the plural, ''moon'' is a completely different word.

===Words without vowels===
{{see also|English words without vowels}}

In rhotic dialects of English, as in Canada and the United States, there are many words such as ''bird, learn, girl, church, worst, worm, [[myrrh]]'' that some phoneticians analyze as having no vowels, only a syllabic consonant {{IPA|/ɹ̩/}}. However, others analyze these words instead as having a [[rhotic vowel]], {{IPA|/ɝː/}}. The difference may be partially one of dialect.

There are a few such words that are disyllabic, like ''[[Wikt:cursor|cursor]], [[curtain]],'' and ''[[turtle]]:'' {{IPA|[ˈkɹ̩sɹ̩]}}, {{IPA|[ˈkɹ̩tn̩]}} and {{IPA|[ˈtɹ̩tl̩]}} (or {{IPA|[ˈkɝːsɚ]}}, {{IPA|[ˈkɝːtən]}}, and {{IPA|[ˈtɝːtəl]}}), and even a few that are trisyllabic, at least in some accents, such as ''purpler'' {{IPA|[ˈpɹ̩.pl̩.ɹ̩]}}, ''hurdler'' {{IPA|[ˈhɹ̩.dl̩.ɹ̩]}}, ''gurgler'' {{IPA|[ˈɡɹ̩.ɡl̩.ɹ̩]}}, and ''certainer'' {{IPA|[ˈsɹ̩.tn̩.ɹ̩]}}.

The word ''and'' frequently contracts to a simple [[nasal consonant|nasal]] ''’n,'' as in ''lock 'n key'' {{IPA|[ˌlɒk ŋ ˈkiː]}}. Words such as ''will, have,'' and ''is'' regularly contract to ''’ll'' {{IPA|[l]}}, ''’ve'' {{IPA|[v]}}, and '''s'' {{IPA|[z]}}. However, none of them are pronounced alone without vowels, so they are not phonological words. [[onomatopoeia|Onomatopoeic]] words that can be pronounced alone, and that have no vowels or ars, include ''hmm, pst!, shh!, [[Dental clicks|tsk]]!,'' and ''zzz''. As in other languages, onomatopoeiae stand outside the normal phonotactics of English.

There are other languages that form lexical words without vowel sounds. In [[Serbo-Croatian]], for example, the consonants {{IPA|[r]}} and {{IPA|[rː]}} (the difference is not written) can act as a [[syllable nucleus]] and carry rising or falling [[tone (linguistics)|tone]]; examples include the tongue-twister {{lang|sh|na vrh brda vrba mrda}} and geographic names such as {{lang|sh|[[Krk]]}}. In [[Czech language|Czech]] and [[Slovak language|Slovak]], either {{IPA|[l]}} or {{IPA|[r]}} can stand in for vowels: {{lang|cs|vlk}} {{IPA|[vl̩k]}} "wolf", {{lang|cs|krk}} {{IPA|[kr̩k]}} "neck". A particularly long word without vowels is {{lang|cs|čtvrthrst}}, meaning "quarter-handful", with two syllables (one for each R), or {{lang|cs|scvrnkls}}, a verb form meaning "you flipped (sth) down" (eg a marble). Whole sentences (usually tongue-twisters) can be made from such words, such as {{lang|cs|[[Strč prst skrz krk]]}}, meaning "stick a finger through your neck" ({{IPA|cs|str̩tʃ pr̩st skr̩s kr̩k|pron|Prst a krk.ogg}}), and {{langx|cs|Smrž pln skvrn zvlhl z mlh|label=none}}, which means "A morel full of spots wetted from fogs". (Here {{lang|cs|zvlhl}} has two syllables based on L; and the [[preposition]] {{lang|cs|z}} consists of a single consonant. Only prepositions do this in Czech, and they normally link phonetically to the following word, so not really behave as vowelless words.) In Russian, there are also prepositions that consist of a single consonant letter, like {{langx|ru|k|lit=to|label=none}}, {{langx|ru|v|lit=in|label=none}}, and {{langx|ru|s|lit=with|label=none}}. However, these forms are actually contractions of {{lang|ru|ko}}, {{lang|ru|vo}}, and {{lang|ru|so}} respectively, and these forms are still used in modern Russian before words with certain consonant clusters for ease of pronunciation.

In [[Kazakh language|Kazakh]] and certain other [[Turkic languages]], words without vowel sounds may occur due to reduction of weak vowels. A common example is the Kazakh word for one: {{lang|kk|bir}}, pronounced {{IPA|[br]}}. Among careful speakers, however, the original vowel may be preserved, and the vowels are always preserved in the orthography.

In Southern [[varieties of Chinese]], such as [[Cantonese]] and [[Southern Min|Minnan]], some monosyllabic words are made of exclusively [[nasal consonant|nasal]]s, such as Cantonese {{IPA|[m̩˨˩]}} "no" and {{IPA|[ŋ̩˩˧]}} "five". Minnan also has words consisting of a consonant followed by a syllabic nasal, such as ''pn̄g'' "cooked rice".

So far, all of these syllabic consonants, at least in the [[lexical words]], have been [[sonorant]]s, such as {{IPA|[r]}}, {{IPA|[l]}}, {{IPA|[m]}}, and {{IPA|[n]}}, which have a [[voice (phonetics)|voiced]] quality similar to vowels. (They can carry tone, for example.) However, there are languages with lexical words that not only contain no vowels, but contain no sonorants at all, like (non-lexical) ''shh!'' in English. These include some [[Berber languages]], some languages of the American [[Pacific Northwest]], such as [[Nuxalk language|Nuxalk]], and some [[Northwest Caucasian languages]], such as [[Abaza language]]. An example from Nuxalk is {{lang|blc|scs}} "seal fat" (pronounced {{IPA|sal|sxs|}}, as spelled), and a longer one is ''[[wikt:xłp̓x̣ʷłtłpłłskʷc̓|clhp'xwlhtlhplhhskwts']]'' (pronounced {{IPA|sal|xɬpʼχʷɬtʰɬpʰɬːskʷʰt͡sʼ|}}) "he had had in his possession a bunchberry plant". (Follow the Nuxalk link for other examples.) Berber examples include {{IPA|/tkkststt/}} "you took it off" and {{IPA|/tfktstt/}} "you gave it". Some words may contain one or two consonants only: {{IPA|/ɡ/}} "be", {{IPA|/ks/}} "feed on".<ref>Audio recordings of selected words without vowels can be downloaded from {{cite web|url=http://ed268.univ-paris3.fr/lpp/pages/EQUIPE/ridouane/audio.doc |title=audio.doc |access-date=2009-06-19 |url-status=dead |archive-url=https://web.archive.org/web/20090320021843/http://ed268.univ-paris3.fr/lpp/pages/EQUIPE/ridouane/audio.doc |archive-date=2009-03-20 }}.</ref> 

Abaza language often drops word-final /ə/ when forming compounds, making combinations such as хъкӏхвбкъвылкӏ /qʰkʼχʷbqʷʼəlkʼ/ "five vats of sour cream" possible. Therefore, even though the dictionary forms хъкӏы /qʰkʼə/ "sour cream" and хвпа /χʷpʰa/ "five" have a [[Ə|schwa]] at the end, the consonant cluster /qʰkʼ/ and the sole consonant /χʷ/ (-pa is a [[Measure word|counting suffix]]) can be analysed as the full word, with final vowels probably being a result of obligatory [[Syllable#Nucleus|nucleus]] (such as in the first example, where the word бкъвыл /bqʷʼəl/ "vat" is a closed syllable, preventing the vowel deletion, unless /l/ is analysed as a [[syllabic consonant]], which would still make it a nucleus but would make the word vowelless). 

In [[Mandarin Chinese]], words and syllables such as {{lang|cmn|sī}} and {{lang|cmn|zhī}} are sometimes described as being syllabic fricatives and affricates phonemically, {{IPA|/ś/}} and {{IPA|/tʂ́/}}, but these do have a voiced segment that carries the tone. 

In the [[Japonic language]] [[Miyako language|Miyako]], there are words with no voiced sounds, such as {{lang|mvi|ss}} 'dust', {{lang|mvi|kss}} 'breast/milk', {{lang|mvi|pss}} 'day', {{lang|mvi|ff}} 'a comb', {{lang|mvi|kff}} 'to make', {{lang|mvi|fks}} 'to build', {{lang|mvi|ksks}} 'month', {{lang|mvi|sks}} 'to cut', {{lang|mvi|psks}} 'to pull'. 

Some analyses of [[Wandala language|Wandala]] is reported to have no phonemic vowels.<ref>{{cite web|last1=Wolff|first1=H. Ekkehard|title='Vocalogenesis' in (Central) Chadic languages|url=http://www.eva.mpg.de/fileadmin/content_files/linguistics/conferences/2015-diversity-linguistics/Wolff_slides.pdf|access-date=2 December 2017}}</ref>

===Words consisting of only vowels===
It is not uncommon for short grammatical words to consist of only vowels, such as ''a'' and ''I'' in English. Lexical words are somewhat rarer in English and are generally restricted to a single syllable: ''eye, awe, owe'', and in non-rhotic accents ''air, ore, err''. Vowel-only words of more than one syllable are generally foreign loans, such as ''ai'' (two syllables: {{IPAc-en|ˈ|ɑː|i}}) for the [[maned sloth]], or proper names, such as ''[[Iowa]]'' (in some accents: {{IPAc-en|ˈ|aɪ|.|oʊ|.|ə}}).

However, vowel sequences in [[hiatus (linguistics)|hiatus]] are more freely allowed in some other languages, most famously perhaps in [[Bantu languages|Bantu]] and [[Polynesian languages|Polynesian]] languages, but also in [[Japanese language|Japanese]] and [[Finnic languages]]. In such languages there tends to be a larger variety of vowel-only words. In [[Swahili language|Swahili]] (Bantu), for example, there is ''[[wikt:aua|aua]]'' 'to survey' and ''[[wikt:eua|eua]]'' 'to purify' (both three syllables); in Japanese, ''[[wikt:aoi|aoi]]'' 青い 'blue/green' and ''[[wikt:oioi|oioi]]'' 追々 'gradually' (three and four [[On (Japanese prosody)|morae]]); and in Finnish, {{lang|fi|aie}} 'intention' and {{lang|fi|auo}} 'open!' (both two syllables), although some dialects pronounce them as {{lang|fi|aije}} and {{lang|fi|auvo}}. In [[Urdu]], āye/aaie {{Script/Nastaliq|آئیے}} or āyn {{Script/Nastaliq|آئیں}} 'come' is used. [[Hawaiian language|Hawaiian]], and the Polynesian languages generally, have unusually large numbers of such words, such as {{lang|haw|aeāea}} (a small green fish), which is three syllables: {{lang|haw|ae.āe.a}}. Most long words involve [[reduplication]], which is quite [[Productivity (linguistics)|productive]] in Polynesian: {{lang|haw|ioio}} 'grooves', {{lang|haw|eaea}} 'breath', {{lang|haw|uaua}} 'tough' (all four syllables), {{lang|haw|auēuē}} 'crying' (five syllables, from {{lang|haw|uē (uwē)}} 'to weep'), {{lang|haw|uoa}} or {{lang|haw|uouoa}} 'false mullet' (sp. fish, three or five syllables).{{citation needed|date=April 2022}}

== See also ==
* [[English phonology]]
* [[Great Vowel Shift]]
* [[Inherent vowel]]
* [[List of phonetics topics]]
* [[Mater lectionis]]
* [[Scale of vowels]]
* [[Table of vowels]]
* [[Vowel coalescence]]
* [[Words without vowels]]
* [[Zero consonant]]

==Notes==
{{notelist}}

== References ==
{{Reflist|30em}}

== Bibliography ==
* ''Handbook of the International Phonetic Association'', 1999. [[Cambridge University]] {{ISBN|978-0-521-63751-0}}
* Johnson, Keith, ''Acoustic & Auditory Phonetics'', second edition, 2003. Blackwell {{ISBN|978-1-4051-0123-3}}
* Korhonen, Mikko. ''Koltansaamen opas'', 1973. Castreanum {{ISBN|978-951-45-0189-0}}
* [[Peter Ladefoged|Ladefoged, Peter]], ''A Course in Phonetics'', fifth edition, 2006. Boston, MA: Thomson Wadsworth {{ISBN|978-1-4130-2079-3}}
* Ladefoged, Peter, ''Elements of Acoustic Phonetics'', 1995. [[University of Chicago]] {{ISBN|978-0-226-46764-1}}
* {{SOWL}}
* Ladefoged, Peter, ''Vowels and Consonants: An Introduction to the Sounds of Languages'', 2000. Blackwell {{ISBN|978-0-631-21412-0}}.
* {{Cite journal | doi = 10.2307/412786 | author = Lindau, Mona. | year = 1978 | title = Vowel features | jstor = 412786| journal = Language | volume = 54 | issue = 3| pages = 541–563 }}
* Stevens, Kenneth N. (1998). ''Acoustic phonetics''. Current studies in linguistics (No. 30). Cambridge, MA: MIT. {{ISBN|978-0-262-19404-4}}.
* {{Cite journal | doi = 10.1121/1.1458026 | author = Stevens, Kenneth N. | year = 2000 | title = Toward a model for lexical access based on acoustic landmarks and distinctive features | journal = The Journal of the Acoustical Society of America | volume = 111 | issue = 4| pages = 1872–1891 | pmid = 12002871 | bibcode = 2002ASAJ..111.1872S | s2cid = 1811670 |s2cid-access=free |url=https://personal.utdallas.edu/~assmann/hcs6367/stevens02.pdf }}
* Watt, D. and Tillotson, J. (2001). "[https://web.archive.org/web/20120412023624/http://www.abdn.ac.uk/langling/resources/Watt-Tillotson2001.pdf A spectrographic analysis of vowel fronting in Bradford English]". ''English World-Wide'' 22:2, 269–302.

==External links==
{{Spoken Wikipedia|Vowel.ogg|date=2005-07-18}}
{{Wiktionary}}
{{Commons category|Vowels}}
*[https://web.archive.org/web/20090403083403/http://www.ling.hf.ntnu.no/ipa/full/ipachart_vowels_fbmp3.html IPA chart] with [[MP3]] sound files
*[http://www.phonetics.ucla.edu/course/chapter1/vowels.html IPA vowel chart] with [[Audio Interchange File Format|AIFF]] sound files
*[http://videoweb.nie.edu.sg/phonetic/vowels/measurements.html Materials for measuring and plotting vowel formants]
*[http://hctv.humnet.ucla.edu/departments/linguistics/VowelsandConsonants/vowels/contents.html Vowels and Consonants] {{Webarchive|url=https://web.archive.org/web/20050703083533/http://hctv.humnet.ucla.edu/departments/linguistics/VowelsandConsonants/vowels/contents.html |date=2005-07-03 }} Online examples from Ladefoged's ''Vowels and Consonants'', referenced above.

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