Diphthongation

A diphthong (/ˈdɪfθɒŋ/ DIF-thong or /ˈdɪpθɒŋ/ DIP-thong; from Greek: δίψθογγος, diphthongos, literally "two sounds" or "two tones"), 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 many dialects of English, the phrase no highway cowboys /ˌnoʊ ˈhaɪweɪ ˈkaʊbɔɪz/ has five distinct diphthongs, one in every syllable.

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