In linguistics and phonology, the schwa is the vowel sound in many lightly pronounced unaccented syllables in English words of more than one syllable. It is sometimes signified by the pronunciation "uh" or symbolized by the symbol ə (an upside-down rotated e). It is the commonest vowel sound in English language. Its sound depends on the adjacent consonants and it is a very short neutral vowel sound.

It is a characteristic of English (and the English accent in other languages) that unaccented neutral vowel sounds, especially before 'r' or 'l', tend to become a schwa. A schwa sound can therefore be represented in English by any vowel. In most dialects, for example, the schwa sound is found in the following words:

• The a in about is a schwa
• The e in synthesis is a schwa
• In American English, the i in decimal is a schwa (not in British English)
• The o in harmony is a schwa
• The u in medium is a schwa
• The y in syringe is a schwa

Authorities vary somewhat in the range of what is considered a schwa sound, but the above examples are generally accepted. This vowel is a consequence of the rhythm of the English language, that makes a great contrast between stressed syllables and unstressed syllables.

For non-English speakers, it may be useful to know that the sound is very similar to a short French unaccented e, or a German ö (an o with umlaut). It is a central, half-open vowel, exactly in the middle of the International phonetic alphabet vowel chart.

Quite a few languages have a schwa sound. It is almost always unstressed. Bulgarian is a language that does allow stressed schwas.

Some browser fonts will show the schwa symbol here: ə. Others may show either a box, a question mark, or capital Y.

The word "schwa" (shəwa, later shəva) originally referred to one of the vowel points used with the Hebrew alphabet, which looks like a vertical pair of dots under a letter. This sign has two uses, one to indicate the schwa vowel-sound and one to indicate the complete absence of a vowel. In practice these two uses do not conflict.

The schwa symbol is used in Azeri as a letter, representing a front a vowel. But using ə, Azeri have problems with Turkish encoding. So, they used ä in their texts before Windows NT appeared.