Triphthong

In phonetics, a triphthong (/ˈtrɪfθɒŋ/ or /ˈtrɪpθɒŋ/) (from Greek τρίφθογγος, "triphthongos", literally "with three sounds," or "with three tones") is a monosyllabic vowel combination involving a quick but smooth movement of the articulator from one vowel quality to another that passes over a third. While "pure" vowels, or monophthongs, are said to have one target articulator position, diphthongs have two, and triphthongs three.

In British Received Pronunciation, (monosyllabic triphthongs with R are optionally distinguished from sequences with disyllabic realizations)

As [eɪ̯] and [əʊ̯] become [ɛə̯] and [ɔː] respectively before /r/, all instances of [eɪ̯.ə] and [əʊ̯.ə] are words with the suffix "-er".

In Cockney, triphthongal realizations [ɪi̯ɐ̯, ɛi̯ə̯, ɔu̯ə̯, æi̯ə̯] of /iə, eə, ɔə, æʊ/ are possible, and are regarded as "very strongly Cockney". Among these, the triphthongal realization of /ɔə/ occurs most commonly. There is not a complete agreement about the distribution of these; according to Wells (1982b), they "occur in sentence-final position", whereas according to Mott (2012), these are "most common in final position".

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