Mid Vowel

A mid vowel is a vowel sound used in some spoken languages. The defining characteristic of a mid vowel is that the tongue is positioned mid-way between an open vowel and a close vowel. The only mid vowel with a dedicated symbol in the International Phonetic Alphabet is the mid central vowel, a symbol which is also used for the vowel schwa.

The IPA divides the vowel space into thirds, with the close-mid vowels such as or and the open-mid vowels such as or equidistant in formant space between open and close or . Thus a true mid front vowel could be transcribed as either a lowered or a raised .

Few languages contrast all three heights of mid vowel, since it is rare for a language to distinguish more than four heights of true front or back vowels. One, the Amstetten dialect of Austro-Bavarian German, contrasts four heights of front unrounded, front rounded, and back vowels in addition to having an open central vowel. These have been transcribed with the available IPA symbols /i e ɛ æ/, /y ø œ ɶ/, /u o ɔ ɑ/, and /a/. The Kensiu language spoken in Malaysia and Thailand is highly unusual in that it contrasts true-mid vowels with close-mid and open-mid vowels without differences in other parameters such as backness or roundedness.

However, the vowels transcribed /æ ɶ ɑ/ are one-third the distance between open /a/ and close /i y u/, precisely the IPA definition of open-mid vowels . Thus Amstetten Bavarian may be an example of a language that contrasts mid vowels with both open-mid and close-mid vowels.