Saturday, September 29, 2007


Note: This page or section contains IPA phonetic symbols in Unicode. See International Phonetic Alphabet for a pronunciation key.
In phonetics, a vowel is a sound in spoken language that is characterized by an open configuration of the vocal tract so that there is no build-up of air pressure above the glottis. This contrasts with consonants, which are characterized by a constriction or closure at one or more points along the vocal tract. A vowel is also understood to be syllabic: an equivalent open but non-syllabic sound is called a semivowel.
In all languages, vowels form the nucleus or peak of syllables, whereas consonants form the onset and (in languages which have them) coda. However, some languages also allow other sounds to form the nucleus of a syllable, such as the syllabic l in the English word table [ˈteɪ.bl̩] (the stroke under the l indicates that it is syllabic; the dot separates syllables), or the r in the Serbo-croatian words vrba [vr̩.ba] "willow" or vrt "garden".
The word vowel comes from the Latin word vocalis, meaning "speaking", because in most languages words and thus speech are not possible without vowels.

Articulation

Main article: Vowel height Height

Main article: Vowel backness Backness

Main article: Vowel roundedness Roundedness

Main article: Nasal vowel Nasalization

Main article: Phonation Phonation
Main articles: Advanced tongue root, Retracted tongue root.
Advanced tongue root (ATR) is a feature common across much of Africa. The contrast between advanced and retracted tongue root resembles the tense/lax contrast acoustically, but they are articulated differently. ATR vowels involve noticeable tension in the vocal tract.

Tongue root retraction

Main article: Pharyngealization Secondary narrowings in the vocal tract

Main article: R-colored vowel Tenseness/checked vowels vs. free vowels
Related article: Phonetics.
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.

Acoustics
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.

Prosody and intonation

Main article: English phonology Pronunciation in English

Main articles: Monophthong, Diphthong, Triphthong, Non-syllabic vowel, and SemivowelVowel Monophthongs, diphthongs, triphthongs
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.

Written vowels

list of phonetics topics
table of vowels
list of vowels
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