Close back rounded vowel

The close back rounded vowel, or high back rounded vowel, is a type of vowel sound used in many spoken languages. The symbol in the International Phonetic Alphabet that represents this sound is ⟨u⟩, and the equivalent X-SAMPA symbol is u.

In most languages, this rounded vowel is pronounced with protruded lips ('endolabial'). However, in a few cases the lips are compressed ('exolabial').

[u] alternates with labio-velar approximant [w] in certain languages, such as French, and in the diphthongs of some languages, [u̯] with the non-syllabic diacritic and [w] are used in different transcription systems to represent the same sound.