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 formants, acoustic resonances 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 vowels have high F1 frequencies while close vowels have low F1 frequencies, as can be seen at right: The [i] and [u] have similar low first formants, whereas [ɑ] has a higher formant.

The second formant, F2, corresponds to vowel frontness. Back vowels have low F2 frequencies while front vowels have high F2 frequencies. This is very clear at right, where the front vowel [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 a better measure of frontness is the difference between the first and second formants. For this reason, vowels are usually plotted as F1 vs. F2 – F1. (This dimension is usually called 'backness' rather than 'frontness', but the term 'backness' can be counterintuitive when discussing formants.)

R-colored vowels are characterized by lowered F3 values.

Rounding is generally realized by a complex relationship between F2 and F3 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 articles: Prosody, Intonation.

The features of vowel prosody are often described independently from vowel quality. In non-linear phonetics, they are located on parallel layers. The features of vowel prosody are usually considered not to apply to the vowel itself, but to the syllable, as some languages do not contrast vowel length separately from syllable length.

Intonation encompasses the changes in pitch, intensity, and speed of an utterance over time. In tonal languages, in most cases the tone of a syllable is carried by the vowel, meaning that the relative pitch or the pitch contour that marks the tone is superimposed on the vowel. If a syllable has a high tone, for example, the pitch of the vowel will be high. If the syllable has a falling tone, then the pitch of the vowel will fall from high to low over the course of uttering the vowel.

Length or quantity refers to the abstracted duration of the vowel. In some analyses this feature is described as a feature of the vowel quality, not of the prosody. Japanese, Finnish, Hungarian, Arabic and Latin have a two-way phonemic contrast between short and long vowels. The Mixe language has a three-way contrast among short, half-long, and long vowels, and this has been reported for a few other languages, though not always as a phonemic distinction. Long vowels are written in the IPA with a triangular colon, which has two equilateral triangles pointing at each other in place of dots ([iː]). The IPA symbol for half-long vowels is the top half of this ([iˑ]). Longer vowels are sometimes claimed, but these are always divided between two syllables.

It should be noted that the length of the vowel is a grammatical abstraction, and there may be more phonologically distinctive lengths. For example, in Finnish, there are five different physical lengths, because stress is marked with length on both grammatically long and short vowels. However, Finnish stress is not lexical and is always on the first two moras, thus this variation serves to separate words from each other.

In non-tonal languages, like English, intonation encompasses lexical stress. A stressed syllable will typically be pronounced with a higher pitch, intensity, and length than unstressed syllables. For example in the word intensity, the vowel represented by the letter 'e' is stressed, so it is longer and pronounced with a higher pitch and intensity than the other vowels.

Pronunciation in English

Main article: English phonology

Monophthongs, diphthongs, triphthongs

Main articles: Monophthong, Diphthong, Triphthong.

A vowel sound whose quality doesn't change over the duration of 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 between 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 [ɪ], the vowel sound in boy is in most dialects a diphthong [ɔɪ], and the vowel sounds of, flower (BrE [aʊə] AmE [aʊɚ]) form a triphthong (disyllabic in the latter cases), although the particular qualities vary by dialect.

The longest sensible word with most consecutive vowels is Finnish riiuuyöaieuutinen, syllabicated rii-uu-yö-ai-e-uu-ti-nen.

In phonology, diphthongs and triphthongs are distinguished from sequences of monophthongs by whether the vowel sound may be analyzed into different phonemes or not. For example, the vowel sounds in a two-syllable pronunciation of the word flower (BrE [flaʊə] AmE [flaʊɚ]) phonetically form a disyllabic triphthong, but are phonologically a sequence of a diphthong (represented by the letters <ow>) and a monophthong (represented by the letters <er>). Some linguists use the terms diphthong and triphthong only in this phonemic sense.

Vowels in languages

The semantic significance of vowels varies widely depending on the language. In some languages, particularly Semitic languages, vowels mostly serve to denote inflections. This is similar to English man vs. men. In fact, the alphabets used to write the Semitic languages, such as the Hebrew alphabet and the Arabic alphabet, do not ordinarily mark all the vowels. These alphabets are technically called abjads. Although it is possible to construct simple English sentences that can be understood without written vowels (cn y rd ths?), extended passages of English lacking written vowels are difficult if not impossible to completely understand (consider dd, which could be any of add, aided, dad, dada, dead, deed, did, died, dodo, dud, dude, eddie, iodide, or odd).

In most languages, vowels are an unchangeable part of the words, as in English man vs. moon which are not different inflectional forms of the same word, but different words. Vowels are especially important to the structures of words in languages that have very few consonants (like Polynesian languages such as Maori and Hawaiian), and in languages whose inventories of vowels are larger than their inventories of consonants.

Vowel systems

Most languages have 3–7 vowels, the following 5-vowel system being the most common:

This configuration is often thought to be particularly stable because it makes efficient use of the vowel space, in that slight variations in one vowel are not confused for another vowel. Spanish and Modern Greek, for example, have this vowel system; Latin had a similar system with the addition of (unwritten) vowel length; it is for this reason that the Latin alphabet has five vowel letters.

All known languages have at least two vowels: Abkhaz, Ubykh, Margi, Eastern Arrernte, and perhaps some of the Ndu languages contrast only two vowels: /a/ and /ɨ/ in the case of Margi, and /a/ and /ə/ for the others, with significant allophony. There have been proposals to reduce the three-vowel inventory of Kabardian to two, one, or even zero vowels (in which case all phonetic vowels would be epenthetic), but most linguists do not believe such analyses are workable. Mandarin has been analysed by some as having two vowels (though with allophones), though this analysis is not totally accepted.[1]

Three-vowel systems have been noted in a large number of languages. These include

• /a, i, u/ (Quechua, many Australian languages, Standard Arabic),
• /i, a, o/ (Pirahã),
• /ɨ, ə, aː/ (Kabardian),
• /i, e, a/ (Wichita).

Some Native American languages, such as Nahuatl and Navajo, have vowel systems that lack /u/^{[citation needed]}, but there is no known language that lacks some form of /a/. At the other end of the spectrum, languages with more than twelve vowels are uncommon, although some widely-spoken languages have large vowel inventories, particularly Germanic languages. For example, English has 14–20 vowels (including diphthongs) depending on dialect, and Swedish has 17 distinct vowel qualities in the height-backness-roundedness spectrum. However, these also involve a length contrast, and the long vowels have diphthongized allophones. Some Norwegian dialects (in the municipalities Tynset and Alvdal in Hedmark county) have 14 standard vowels (with additional length contrast).^{[citation needed]} The oldest form of Norse (before 1200) had nine vowels (a, e, i, o, u, y, æ, ø and ǫ), and all these could be short oral vowels, long oral vowels or long nasal vowels for a total of 27 distinct monophthongs. There were also three diphthongs (au, ei and ey).

French has 16 short monophthongal vowel qualities, including nasals, and Portuguese has 12 to 14, depending on dialect. The previously-mentioned Sedang has 24 distinct monophthongs, which it achieves by contrasting phonation on seven vowel qualities. Juǀʼhoan uses phonation and nasalization with five vowel qualities to achieve approximately 40 vowels, most of which may in addition occur both long and short.^{[citation needed]}

Written vowels

Main article: Writing system

The name "vowel" is often used for the symbols used for representing vowel sounds in a language's writing system, particularly if the language uses an alphabet. In the Latin alphabet, the vowel letters are A, E, I, O, U, and Y; in addition, extensions of the Latin alphabet have independent vowel letters such as Ä, Ö, Ü, Å, Æ, and Ø. The phonetic values vary by language, and some languages use I and Y for the consonant [j], e.g. initial I in Romanian and initial Y in English. Some languages using the Latin alphabet may use other letters to represent vowel sounds: for example, in Welsh, the letter W stands for [u] or [ʊ], while in Creek the letter V stands for [ə].

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 the case of English, the five primary vowel letters can represent a variety of vowel sounds.

Other languages cope with the limitation in the number of Latin vowel letters in similar ways. Many languages, like English, make extensive use of combinations of vowel letters to represent various sounds. Other languages use vowel letters with modifications, e.g. Ä in Finnish, or add diacritical marks to vowels, such as accents or umlauts, 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 æ or ø that are found in some of the Scandinavian languages. The International Phonetic Alphabet has a set of 28 symbols to represent the range of basic vowel qualities, and a further set of diacritics to denote variations from the basic vowel.

Written vowels in writing systems

• Arabic: long vowels: ا و ي; short vowels: ِ ُ َ
• Armenian: ա ե է ը ի ո օ ու իւ էօ
• Azeri: a e ə ı i o ö u ü
• Bielarus: non-iotated ('hard'): А О У Ы Э; iotated ('soft'): Я Ё Ю І Е
• Bulgarian: non-iotated ('hard'): А О У Ъ; iotated ('soft'): Я Ю И Е
• Czech: a e i o u y, long with an acute á é í ó ú ý or a ring ů, softening ě
• Danish, Norwegian, and Swedish: back ('hard'): a o u å; front ('soft'): e i y æ/ä ø/ö
• Devanagari: Independent vowels: अ आ इ ई उ ऊ ए ऐ ओ औ; Dependent vowels: ा ि ी ु ू े ै ो ौ
• Estonian and Võro: a e i o u ü ä ö õ (y); half-long and over-long vowels doubled
• French: oral: i é è a o ou e eu u; nasal: an on in un
• Finnish: back: a o u; neutral: i e; front: ä ö y; long vowels doubled (aamu, uuma, etc.)
• Greek: α ε η ι ο υ ω
• Guaraní: oral: a e i o u y; nasal: ã ẽ ĩ õ ũ ỹ
• German: a ä e i o ö u ü y
• Korean: ㅏ ㅐ ㅑ ㅒ ㅓ ㅔ ㅕ ㅖ ㅗ ㅘ ㅙ ㅚ ㅛ ㅜ ㅝ ㅞ ㅟ ㅠ ㅡ ㅢ ㅣ
• Hebrew: ֱ ֲ ֳ ְ ֻ ֹ ִ ֵ ֶ ַ ָ (see Niqqud)
• Hungarian: a, á, e, é, i/í, o/ó, ö/ő, u/ú, ü/ű. (Only those written in pairs are of the same quality.)
• Japanese: normal: あいうえお; grammatical: へを
• Italian: a e i o u
• Latin: a e i o u y
• Polish: a ą e ę i o ó u y
• Russian: non-iotated ('hard'): А О У Ы Э; iotated ('soft'): Я Ё Ю И Е
• Skolt Sami: u o õ å a, i e â ä (normal); long vowels doubled (lääij, nââ'ǩǩted, etc.).
• Slovak: a ä e i o u y, long with an acute á é í ó ú ý (+ l, r and long ĺ, ŕ)
• Tamil: அ (ha), ஆ (hā), இ (e), ஈ (ē), உ (u), ஊ (ū), எ (a), ஏ (ā), ஐ (i), ஒ (o), ஓ (ō), ஔ (au)
• Turkish: a ı o u ('thick'), e i ö ü ('thin')
• Vietnamese: a ă â e ê i o ô ơ u ư y, plus tonal marks (e.g. ầ, ứ, ...).
• Ukrainian: non-iotated ('hard'): А О У Е И; iotated ('soft'): Я Ї Ю Є I

See also

• list of phonetics topics
• table of vowels
• list of vowels

References

• Handbook of the International Phonetic Association, 1999. Cambridge University ISBN 0-521-63751-1
• Johnson, Keith, Acoustic & Auditory Phonetics, second edition, 2003. Blackwell ISBN 1-4051-0123-7
• Ladefoged, Peter, A Course in Phonetics, fourth edition, 2000. Heinle ISBN 0-15-507319-2
• Ladefoged, Peter, Elements of Acoustic Phonetics, 1995. University of Chicago ISBN 0-226-46764-3
• Ladefoged, Peter and Ian Maddieson, The Sounds of the World's Languages, 1996. Blackwell ISBN 0-631-19815-6
• Ladefoged, Peter, Vowels and Consonants: An Introduction to the Sounds of Languages, 2000. Blackwell ISBN 0-631-21412-7.
• Lindau, Mona. (1978). Vowel features. Language, 54, 541-563.
• Stevens, Kenneth N. (1998). Acoustic phonetics. Current studies in linguistics (No. 30). Cambridge, MA: MIT. ISBN 0-262-19404-X.
• Stevens, Kenneth N. (2000). Toward a model for lexical access based on acoustic landmarks and distinctive features. The Journal of the Acoustical Society of America, 111 (4), 1872-1891.
• Korhonen, Mikko. Koltansaamen opas, 1973. Castreanum ISBN 951-45-0189-6

External links

• Vowels and Consonants Online examples from Ladefoged's Vowels and Consonants, referenced above.
• Dictionary of All-Vowel Words: a free online dictionary with over 1,000 words with no consonants and examples of usage from literature.