The near-close near-back vowel, or near-high near-back vowel, is a type of vowel sound, used in some vocal languages. The IPA symbol for the near-close near-back rounded vowel 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.
The IPA prefers the 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".
Some languages may have a near-close near-back unrounded vowel, which can be represented with ⟨ɯ̽⟩ or ⟨ʊ̜⟩ in the IPA, or sometimes with the old convention of ⟨ω⟩. A near-close near-back compressed vowel can be transcribed ⟨ʊᵝ⟩.
Iivonen, Antti; Harnud, Huhe (2005), "Acoustical comparison of the monophthong systems in Finnish, Mongolian and Udmurt", Journal of the International Phonetic Association35 (1): 59–71, doi:10.1017/S002510030500191X
Kohler, Klaus J. (1999), "German", Handbook of the International Phonetic Association: A guide to the use of the International Phonetic Alphabet, Cambridge: Cambridge University Press, pp. 86–89, ISBN0-521-65236-7
Ladefoged, Peter (1999), "American English", Handbook of the International Phonetic Association, Cambridge University Press, pp. 41–44
Lee, Hyun Bok (1999), "Korean", Handbook of the International Phonetic Association, Cambridge University Press, pp. 120–122, ISBN0-521-63751-1