Certain suffixes also distinguish between front unrounded vowels and front rounded vowels. For open central unrounded vowels transcribed with , see open central unrounded vowel. Vowels can be grouped as back rounded, front unrounded and front rounded. Azerbaijani's system of vowel harmony has both front/back and rounded/unrounded vowels. Vowels can be categorized as rounded or unrounded. Vowels can be grouped as front unrounded, front rounded, central and back. The mid central unrounded vowel is frequently written with the symbol . Most languages have some form of an unrounded open vowel. Many languages have some form of an unrounded open vowel. The Azerbaijani language also has , which represents the near-open front unrounded vowel. No distinction is made between front and central for the lowest unrounded vowels. Together, they form a symbol that represents the open central unrounded vowel, . The lip position of unrounded vowels may be classified into two groups&colon; "spread" and "neutral". In the case of "u-umlaut", this entails labialization of unrounded vowels. It is realized as with a central off-glide preceding both unrounded and rounded uvulars.