Vowel Roundness

Vowel roundness is the position of the lips when pronouncing vowels.

Rounded Vowels
Rounded vowels are pronounced with the lips rounded and pushed forward. Rounding the lips lengthens the mouth just like pulling the tongue back, and that's why back vowels are prototypically rounded. The height of the vowels affects their roundness too: higher rounded vowels tend to be more rounded than lower rounded vowels.

Unrounded Vowels
Unrounded vowels are vowels that are not pronounced with the lips rounded and pushed forward. There are two types of unrounded vowels: spread vowels and neutral vowels.

Spread Vowels
Spread vowels are pronounced with the lips stretched to the sides. Spreading the lips shortens the mouth just like pushing the tongue forward, and that's why front vowels are prototypically spread. just like roundness, the height of the vowels affects their spreadness too: higher spread vowels tend to be more spread than lower spread vowels.

Neutral Vowels
Neutral vowels are pronounced with the lips relaxed. Central vowels are prototypically neutral, and they usually don't have the same height as front and back vowels.

Vowel Roundness in Orish
In Orish, roundness is not a phonemic feature of vowels, but it's still important for the quality of the vowels. Back vowels are rounded, Front vowels are spread, and central vowels are neutral.