In phonetics, vowel roundedness refers to the amount of rounding in the lips during the articulation of a vowel. When pronouncing a rounded vowel, the lips form a circular opening, while unrounded vowels are pronounced with the lips relaxed. In most languages, front vowels tend to be unrounded, while back vowels tend to be rounded, but some languages, such as French and German, distinguish between rounded and unrounded vowels at the same height and backness.

In the International Phonetic Alphabet vowel chart, rounded vowels are the ones that occur on the right in each pair of vowels.

Types of rounding

There are two types of vowel rounding: endolabial and exolabial. In endolabial rounding, the corners of the mouth are drawn slightly together to form a circular opening, but the lips do not protrude and only the outer surface of the lips is exposed. In exolabial rounding, the lips are thrust forward to form a tunnel, as when kissing; the inner surface of the lips is exposed. Usually, back rounded vowels are exolabial, while front rounded vowels are endolabial. Swedish is uncommon in that it makes a phonemic distinction between the two types, having unrounded, endolabial, and exolabial front close-mid vowels.

See also

• List of phonetics topics