In linguistics, specifically phonetics and phonology, schwa ( or rarely ) (sometimes spelled shwa) refers to the mid-central vowel sound (rounded or unrounded) in the middle of the vowel chart, denoted by the IPA symbol , or another vowel sound close to that position. An example in English is the vowel sound in the 'a' of the word 'about'. Schwa in English is mainly found in unstressed positions, but in some other languages it occurs more frequently as a stressed vowel.