 in phonetics, vowel roundedness refers to the amount of rounding in the lips during the articulation of a vowel. it is labialization of a vowel. when pronouncing a rounded vowel, the lips form a circular opening, while unrounded vowels (also called spread 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 rounded and unrounded front vowels of the same height, while vietnamese distinguishes rounded and unrounded back vowels of the same height. gahuku has all unrounded vowels. in the international phonetic alphabet vowel chart, rounded vowels are the ones that appear on the right in each pair of vowels. there are also diacritics,  and , to indicate greater and lesser degrees of rounding, respectively. these 'more' and 'less rounded' diacritics are sometimes also used with consonants to indicate degrees of labialization. ==types of rounding==  {|align="right" |valign="top"|left|150px|thumb|compressed rounding (example 1) |valign="top"|left|150px|thumb|protruded rounding (example 1) |- |valign="top"|left|150px|thumb|compressed rounding (example 2) |valign="top"|left|150px|thumb|protruded rounding (example 2) |} there are two types of vowel rounding: protrusion and compression.endolabial: also called protruded, lip-pouting, horizontal lip-rounding, outrounding, and inner rounding (trask 1996:180)exolabial: also called compressed, pursed, vertical lip-rounding, inrounding, or outer rounding (trask 1996:252)henry sweet noted in 1890 that "the term 'inner rounding' derives from the use of the inner surfaces of the lips; the synonymous 'outrounding' derives from the forward projection of the lips. both terms are justifiable, but their coexistence is likely to lead to serious confusion." (trask 1996:180.) in protruded rounding, the corners of the mouth are drawn together and the lips protrude like a tube, with their inner surface visible. in compressed rounding, the corners of the mouth are drawn together, but the lips are also drawn together horizontally ("compressed") and do not protrude, with o
Labial_consonants Vowels