IPA number 321 Unicode (hex) U+028A Kirshenbaum U | Entity (decimal) ʊ X-SAMPA U | |
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The near-close near-back rounded vowel, or near-high near-back rounded vowel, is a type of vowel sound, used in some vocal languages. The IPA symbol that represents this sound is ⟨ʊ⟩. It is informally called "horseshoe u". Prior to 1989, there was an alternate IPA symbol for this sound, ⟨ɷ⟩, called "closed omega"; use of this symbol is no longer sanctioned by the IPA. In Americanist phonetic notation, the symbol ⟨ᴜ⟩ (a small capital U) is used. Sometimes, especially in broad transcription, this vowel is transcribed with a simpler symbol ⟨u⟩, which technically represents the close back rounded vowel.
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The Handbook of the International Phonetic Association defines [ʊ] as a mid-centralized (lowered and centralized) close back rounded vowel, therefore, an alternative transcription of this vowel is ⟨u̽⟩ (a symbol equivalent to a more complex ⟨ü̞⟩). The symbol ⟨ʊ⟩ is often also used to transcribe the close-mid near-back rounded vowel, which is a slightly lower vowel, though it still fits the definition of a mid-centralized [u]. It occurs in some dialects of English (such as General American and Geordie) as well as some other languages (such as Maastrichtian Limburgish). It can be transcribed with the symbol ⟨ʊ̞⟩ (a lowered ⟨ʊ⟩) in narrow transcription. Certain sources may even use ⟨ʊ⟩ for the close-mid back rounded vowel, but that is rare. For the close-mid (near-)back rounded vowel that is not usually transcribed with the symbol ⟨ʊ⟩ (or ⟨u⟩), see close-mid back rounded vowel.
For the fully central equivalents of these vowels, see near-close central rounded vowel and close-mid central rounded vowel.
Some languages, such as Bengali and Korean have the near-close back rounded vowel, which differs from its near-back counterpart in that it is a lowered, but not centralized close back rounded vowel, transcribed in the IPA as ⟨ʊ̠⟩, ⟨u̞⟩ or ⟨o̝⟩.
There is even one language (Palula) that contrasts a long near-close back rounded vowel with a short close-mid near-back rounded vowel, but they tend to be transcribed simply as /uː/ and /u/.
The IPA prefers the terms "close" and "open" for vowels, and the name of the article follows this. However, the terms "high" and "low" are also in widespread use.
A few languages also have the near-close near-back unrounded vowel (which does not have a separate IPA symbol) in their inventory.
Near-close near-back protruded vowel
The near-close near-back protruded vowel is typically transcribed in IPA simply as ⟨ʊ⟩, and that is the convention used in this article. As there is no dedicated diacritic for protrusion in the IPA, symbol for the near-close near-back rounded vowel with an old diacritic for labialization, ⟨ ̫⟩, can be used as an ad hoc symbol ⟨ʊ̫⟩ for the near-close near-back protruded vowel. Another possible transcription is ⟨ʊʷ⟩ or ⟨ɯ̽ʷ⟩ (a near-close near-back vowel modified by endolabialization), but this could be misread as a diphthong.
The close-mid near-back protruded vowel can be transcribed ⟨ʊ̞ʷ⟩ or ⟨ʊ̫˕⟩, whereas the near-close back protruded vowel can be transcribed ⟨u̞ʷ⟩, ⟨ɯ̞ʷ⟩ or ⟨u̫˕⟩.
Features
Near-close near-back compressed vowel
Some languages, such as Norwegian, are found with a near-close near-back vowel that has a distinct type of rounding, called compressed or exolabial.
There is no dedicated diacritic for compression in the IPA. However, the compression of the lips can be shown with the letter ⟨β̞⟩ as ⟨ɯ̽͡β̞⟩ (simultaneous [ɯ̽] and labial compression) or ⟨ɯ̽ᵝ⟩ ([ɯ̽] modified with labial compression). The spread-lip diacritic ⟨ ͍ ⟩ may also be used with a rounded vowel letter ⟨ʊ͍⟩ as an ad hoc symbol, though technically 'spread' means unrounded.
Only the Shanghainese dialect is known to contrast this with the more typical protruded (endolabial) near-close near-back vowel, although the height of both of these vowels varies from close to close-mid.
The near-close back compressed vowel can be transcribed ⟨ɯ̞͡β̞⟩, ⟨ɯ̞ᵝ⟩ or ⟨u͍˕⟩.