The mid front rounded vowel is a type of vowel sound, used in some spoken languages.
Although there is no dedicated symbol in the International Phonetic Alphabet that represents the "exact" mid front rounded vowel between close-mid [ø] and open-mid [œ], ⟨ø⟩ is generally used. If precision is desired, diacritics can be used, such as ⟨ø̞⟩ or ⟨œ̝⟩.
Its vowel backness is front, which means the tongue is positioned as far forward as possible in the mouth without creating a constriction that would be classified as a consonant. Note that rounded front vowels are often centralized, which means that they're in fact near-front.
Its roundedness is compressed, which means that the margins of the lips are tense and drawn together in such a way that the inner surfaces are not exposed.
Catford notes that most languages with rounded front and back vowels use distinct types of labialization, protruded back vowels and compressed front vowels. However, a few languages, such as Scandinavian ones, have protruded front vowels. One of these, Swedish, even contrasts the two types of rounding in front vowels (see near-close near-front rounded vowel, with Swedish examples of both types of rounding).
As there are no diacritics in the IPA to distinguish protruded and compressed rounding, ⟨ø̞ʷ⟩ (a mid front rounded vowel modified by endolabialization) will be used here as an ad hoc symbol for protruded mid front vowels.
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