A diphthong (or; from Greek, 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 has five distinct diphthongs, one in every syllable.
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