Diphthong

A diphthong (ˈdɪfθɒŋ,_ˈdɪp- ; , ), also known as a gliding vowel, is a combination of two adjacent vowel sounds within the same syllable. Technically, a diphthong is a vowel with two different targets: that is, the tongue (and/or other parts of the speech apparatus) moves during the pronunciation of the vowel. In most varieties of English, the phrase "no highway cowboy" (noʊ_ˈhaɪweɪ_ˈkaʊbɔɪ) has five distinct diphthongs, one in every syllable. Diphthongs contrast with monophthongs, where the tongue or other speech organs do not move and the syllable contains only a single vowel sound. For instance, in English, the word ah is spoken as a monophthong (ɑː), while the word ow is spoken as a diphthong in most varieties (aʊ). Where two adjacent vowel sounds occur in different syllables (e.g. in the English word re-elect) the result is described as hiatus, not as a diphthong. (The English word hiatus (ˌhaɪˈeɪtəs) is itself an example of both hiatus and diphthongs.) Diphthongs often form when separate vowels are run together in rapid speech during a conversation. However, there are also unitary diphthongs, as in the English examples above, which are heard by listeners as single-vowel sounds (phonemes). In the International Phonetic Alphabet (IPA), monophthongs are transcribed with one symbol, as in English sun [sʌn], in which ʌ represents a monophthong. Diphthongs are transcribed with two symbols, as in English high /haɪ/ or cow /kaʊ/, in which aɪ and aʊ represent diphthongs. Diphthongs may be transcribed with two vowel symbols or with a vowel symbol and a semivowel symbol. In the words above, the less prominent member of the diphthong can be represented with the symbols for the palatal approximant j and the labiovelar approximant w, with the symbols for the close vowels i and u, or the symbols for the near-close vowels ɪ and ʊ: Some transcriptions are broader or narrower (less precise or more precise phonetically) than others.