u

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.
The IPA prefers terms "close" and "open" for vowels, and the name of the article follows this. However, a large number of linguists, perhaps a majority, prefer the terms "high" and "low".
In most languages this rounded vowel is pronounced with protruded lips ('endolabial'). However, in a few cases the lips are compressed ('exolabial').
The close back rounded vowel is almost identical featurally to the labio-velar approximant [w]. [u] alternates with [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.

Features

• Its vowel height is close, also known as high, which means the tongue is positioned as close as possible to the roof of the mouth without creating a constriction that would be classified as a consonant.
• Its vowel backness is back, which means the tongue is positioned as far back as possible in the mouth without creating a constriction that would be classified as a consonant. Note that unrounded back vowels tend to be centralized, which means that they're in fact near-back.
• Its roundedness is protruded, which means that the corners of the lips are drawn together, and the inner surfaces exposed.