Vowel soundsPhonetically a vowel is a speech sound characterized by voicing (the vibration of the larynx) and by absence of obstruction or audible friction in the vocal tract, allowing the breath free passage. The quality of a vowel is chiefly determined by the position of the tongue and the lips: see VOWEL QUALITY. Vowel sounds divide into MONOPHTHONGS (single vowel sounds that may be long or short), DIPHTHONGS (double vowel sounds formed by gliding from one vowel position to another), and triphthongs (triple vowel sounds formed by gliding from one through another to a third vowel position). The human speech mechanism is capable of producing a wide range of simple and complex vowel sounds. As with consonants, however, in each language (or language variety) a particular range of vowels is used: for example, in standard Parisian French, there are 12 non-nasal and 4 nasal monophthongs (16 vowel sounds in all); in BrE, the basic vowel system of RP has 12 monophthongs and 8 diphthongs (20 vowel sounds in all) while the basic vowel system of ScoE has 10 monophthongs and 4 diphthongs (14 vowel sounds in all).
Vowel lettersThe five classic vowel letters of the Roman alphabet are A, E, I, O, U, to which Y is usually added; apart from its syllable-initial role as a semi-vowel or semi-consonant in words like year, y functions in English largely as an alternative vowel symbol to i. Phonetically, the letters w (as in win) and y (as in year) are articulated similarly to vowels, but positionally they function as consonants, initiating syllables and introducing vowels: compare wear/bear and year/fear. Phonetically, too, the liquid consonants written as l, r and the nasal consonants written as m, n have some of the characteristics of vowels (such as continuous non-fricative voicing), and when used syllabically (as in the pronunciations of apple, spasm, isn't, centre) they in effect represent a preceding SCHWA vowel sound in addition to their own sound value.
Whereas the five classic vowel letters match the five vowel phonemes of a language like Spanish, they are insufficient to distinguish the much larger number of vowel phonemes of English. When unaccompanied by another vowel letter, the five letters usually have a basic ‘short’ sound value in medial position in English words (as in pat, pet, pit, pot, putt/put), but in some words (such as yacht, pretty, son, busy) their values are aberrant, and in certain environments, such as after /w/ and before /l, r/, they are commonly modified (as in was, word, all, old, far, her, fir, for, fur). For each of the short values there is a corresponding ‘long’ value which formerly (before the GREAT VOWEL SHIFT of the 15c) was close to the short value, but is today in varying degrees removed from it (and is not the ‘long’ value as understood in phonetics). The present-day long values are as heard in mate, meet, might, moat, mute. Native speakers perceive the long values as intimately associated with the short values; the two often alternate in related words (as in sane/sanity, abbreviate/brevity, five/fifth, depose/deposit, student/study) and the long values are heard as the names of the letters themselves (heard as ay, ee, eye, oh, you).
The spelling of the long values of the vowels is varied and unpredictable: for example, Edward Rondthaler and Edward J. Lias (Dictionary of American Spelling, 1986) list 114 alternative spellings for the five sounds. These include single graphemes (units of writing), as in mind, post, truth, DIGRAPHS as in leave, sleeve, receive, believe, and longer graphemes as in beau, queue. Some of these longer graphemes include consonant letters (as in the eigh of weigh and the et of ballet) that are in effect constituents of vowels. Highly characteristic of English vowel spellings is the ‘magic’ e placed after a consonant, which has the effect in Modern English of showing the long value of a preceding vowel, as in mate, mete, mite, mote, mute. In addition to these parallel sets of short and long vowels corresponding to a, e, i, o, u, English also needs to spell several vowel sounds for which alternative pairs of digraphs are widely (but not consistently) used according to position: for example, initial and medial au, eu, ou, ai, oi, but final aw, ew, ow, ay, oy (contrast fault/flaw, feud/few, count/cow, rain/ray, coil/coy). A corollary of the many alternative spellings for the same vowel sound is the many alternative pronunciations that may be required for the same vowel letters: for example, ea is pronounced in nine different ways in eat, threat, great, react, create, pear, hear, heart, hearse.
See ABLAUT, ACCENT, APHESIS, DIACRITIC, DIAERESIS, ELISION, EPENTHESIS, LIGATURE, RECEIVED PRONUNCIATION, RHYTHM, SPELLING, STRESS, SYLLABLE, VOWEL QUANTITY, VOWEL SHIFT, WEAK VOWEL.
vow·el / ˈvouəl/ • n. a speech sound that is produced by comparatively open configuration of the vocal tract, with vibration of the vocal cords but without audible friction and is a unit of the sound system of a language that forms the nucleus of a syllable. Contrasted with consonant. ∎ a letter representing such a sound, such as a, e, i, o, u.