In phonetics, a diphthong is a combination of two adjacent vowel sounds pronounced within the same syllable. In the [[International Phonetic Alphabet (IPA)]] diphthongs are transcribed with two symbols, as in English _high_ /haj/ or _cow_ /kaw/, in which ⟨aɪ⟩ and ⟨aw⟩ are diphthongs. A diphthong may be transcribed with a vowel symbol and a [[semi-vowel]] symbol or with two vowel symbols.