Mid central vowel

The mid central vowel (also known as schwa) is a type of vowel sound, used in some spoken languages. The symbol in the International Phonetic Alphabet that represents this sound is ⟨ə⟩, a rotated lowercase letter e.

While the Handbook of the International Phonetic Association does not define the roundedness of [ə],[1] it is more often unrounded than rounded. The phonetician Jane Setter describes the pronunciation of the unrounded variant as follows: "[ə] is a sound which can be produced by basically relaxing the articulators in the oral cavity and vocalising."[2] To produce the rounded variant, all that needs to be done in addition to that is to round the lips.

Afrikaans contrasts unrounded and rounded mid central vowels; the latter is usually transcribed with ⟨œ⟩. The contrast is not very stable, and many speakers use an unrounded vowel in both cases.[3]

Some languages, such as Danish[4] and Luxembourgish,[5] have a mid central vowel that is variably rounded. In some other languages, things are more complicated, as the change in rounding is accompanied with the change in height and/or backness. For instance, in Dutch, the unrounded allophone of /ə/ is mid central unrounded [ə], but its word-final rounded allophone is close-mid front rounded [ø̜], close to the main allophone of /ʏ/.[6]

The symbol ⟨ə⟩ is often used for any unstressed obscure vowel, regardless of its precise quality. For instance, the English vowel transcribed ⟨ə⟩ is a central unrounded vowel that can be close-mid [ɘ], mid [ə] or open-mid [ɜ], depending on the environment.[7]

The mid central unrounded vowel is frequently written with the symbol [ə]. If greater precision is desired, the symbol for the close-mid central unrounded vowel may be used with a lowering diacritic, [ɘ̞]. Another possibility is using the symbol for the open-mid central unrounded vowel with a raising diacritic, [ɜ̝].

Languages may have a mid central rounded vowel (a rounded [ə]), distinct from both the close-mid and open-mid vowels. However, since no language is known to distinguish all three, there is no separate IPA symbol for the mid vowel, and the symbol [ɵ] for the close-mid central rounded vowel is generally used instead. If precision is desired, the lowering diacritic can be used: [ɵ̞]. This vowel can also be represented by adding the more rounded diacritic to the schwa symbol, or by combining the raising diacritic with the open-mid central rounded vowel symbol, although it is rare to use such symbols.