|Mid back rounded vowel
Legend: unrounded • rounded
The mid back rounded vowel is a type of vowel sound, used in some spoken languages. While there is no dedicated symbol in the International Phonetic Alphabet that represents the exact mid back rounded vowel between close-mid [o] and open-mid [ɔ], it is normally written ⟨o⟩. If precision is desired, diacritics may be used, such as ⟨o̞⟩ or ⟨ɔ̝⟩, the former being more common. There was an alternative IPA symbol for this sound, ⟨ꭥ⟩. A non-IPA letter ⟨ⱺ⟩ is also found.
Just because a language has only one non-close non-open back vowel, it still may not be a true-mid vowel. Tukang Besi is a language in Sulawesi, Indonesia, with a close-mid [o]. Taba, another language in Indonesia, in the Maluku Islands, has an open-mid [ɔ]. In both languages, there is no contrast with another mid (true-mid or close-mid) vowel.
Kensiu, in Malaysia and Thailand, is highly unusual in that it contrasts true-mid vowels with close-mid and open-mid vowels without any difference in other parameters, such as backness or roundedness.