In phonetics, a triphthong /ˈtrɪfθɒŋ/ (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.

English 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".

Bernese German (a Swiss German dialect):

Latvian:

Northern Austro-Bavarian:

The Northern Austro-Bavarian triphthongs have evolved from combinations of former long vowels or diphthongs from the Middle High German (MHG) period and vocalized r.

Portuguese:

Some Portuguese triphthongs appears in places where some speakers can break the first segment to form a hiatus (that is, [i̯] or [u̯] are not equivalent to standard Portuguese semivowels [j] and [w] in this case), and as such they are deemed as non-triphthongs by standard, although many or most speakers produce them as such (and even more frequently when speaking colloquially):