The word schwa is from the Hebrew word shva (שְׁוָא shewa’,, modern shva), which designates the Hebrew niqqud vowel sign shva "ְ" that in modern Hebrew indicates either the phoneme /e/ or the complete absence of a vowel. Also the Hebrew shva is sometimes represented by the upside-down e symbol for schwa, a misleading transliteration, since the schwa vowel is not representative of modern Hebrew pronunciation of shva and is not characteristic of earlier pronunciations either (see Tiberian vocalization → Mobile Shwa). The term was introduced into European linguistics by Jacob Grimm in the early 19th century, so the spelling sch is German in origin. It was first used in English texts between 1890–1895.
See main article: Epenthesis, Unstressed vowel and Vowel reduction. Sometimes the term "schwa" is used for any epenthetic vowel, even though different languages use different epenthetic vowels (e.g., the Navajo epenthetic vowel is).
In English, schwa is the most common vowel sound. It is a reduced vowel in many unstressed syllables, especially if syllabic consonants are not used. Depending on dialect, it may correspond to any of the following orthographic letters:
Schwa is a very short neutral vowel sound, and like all vowels, its precise quality varies depending on the adjacent consonants. In most varieties of English, schwa mostly occurs in unstressed syllables (exceptions include BrE concerted), but in New Zealand English and South African English the high front lax vowel (as in the word bit) has shifted open and back to sound like schwa, and these dialects include both stressed and unstressed schwas. In General American, schwa is one of the two vowel sounds that can be rhotacized. This sound is used in words with unstressed "er" syllables, such as dinner.
Quite a few languages have a sound similar to schwa. It is similar to a short French unaccented e, which in that language is rounded and less central, more like an open-mid or close-mid front rounded vowel. It is almost always unstressed, though Albanian, Bulgarian, Slovene and Afrikaans are some of the languages that allow stressed schwas. In most dialects of Russian an unstressed a or o reduces to a schwa. In dialects of Kashubian a schwa occurs. Many Caucasian languages and some Uralic languages (e.g. Komi) also use phonemic schwa, and allow schwas to be stressed. In Dutch, the vowel of the suffix -lijk, as in waarschijnlijk (probably) is pronounced as a schwa. In Dutch adjective words carry a schwa at their ending 'rood' becomes 'rode'. Anytime an 'e' falls at the end of Dutch words it becomes a schwa. Compare 'de' and 'het'. In the Eastern dialects of Catalan, including the standard language variety, based in the dialect spoken in and around Barcelona, an unstressed "a" or "e" is pronounced as a schwa (called "vocal neutra", "neutral vowel"). In the dialects of Catalan spoken in the Balearic Islands, a stressed schwa can occur. Stressed schwa can occur in Romanian as in mătură ('broom'). In European and some African dialects of Portuguese, the schwa occurs in many unstressed syllables that end in "e", such as noite (night), tarde (afternoon, late), pêssego (peach), and pecado (sin). However, that is rare in Brazilian Portuguese except in such areas as Curitiba in the state of Paraná. In Neapolitan a final,unstressed "a", and unstressed "e" and "o" are pronounced as a schwa : pìzza (pizza), semmàna (week), purtuàllo (orange) . The inherent vowel in the Devanagari script, an abugida used to write Hindi, Marathi, Nepali, and Sanskrit is a schwa, written अ in isolation or to begin a word.
Other characters used to represent this sound include in Armenian, in Romanian, and ë in Albanian. In Bulgarian Cyrillic, the letter , which has a much different orthographic function in modern Russian, is used. In Korean, the letter (or rather jamo) ㅡ is used, though it may also represent a "null" vowel used in the transcription of foreign consonant clusters, where it may be deleted.
In Indonesian, schwa can be stressed or not. Most of the times, the letter
There is also a phenomenon of pronouncing the a in the final syllable (usually second syllable, since most Indonesian root words consist of two syllables) as a stressed schwa. This is only done in colloquial informal speech but never in formal speech.
Indonesian orthography formerly used unmarked
In the 1972 spelling reform that unified Indonesian and Malaysian spelling conventions (Ejaan yang Disempurnakan, regulated by MABBIM), it was agreed to use neither diacritic. Hence there is no orthographic distinction any longer between /ə/ and /e/; both are spelled with unmarked
In southern Malaysian pronunciation, which is considered the standard, the final letter -a represents schwa, while final -ah stands for /a/. The dialect of Kedah in northern Malaysia, however, pronounces final -a as /a/ also. In loanwords, a nonfinal short /a/ may become schwa in Malay. For example, Mekah (
In Albanian, schwa is represented by the letter Ë, ë, which is also one of the letters of the Albanian alphabet, coming right after the letter E. Schwa in Albanian can be stressed like in words "" and "" (sweet and dream).
When the new Latin alphabet was introduced for the Azerbaijani language on December 25, 1991, A-umlaut was selected to represent the sound /æ/. However, on May 16, 1992, it was replaced by the schwa letter, which also employs a capital form "Ə". Although use of "Ä"/"ä" (also used in Tatar, Turkmen, and Gagauz) seems to be a simpler alternative as the schwa letter is absent in several character sets, particularly Turkish encoding, it was reintroduced; the schwa letter was used continuously from 1929 to 1991 to represent Azeri's most-common vowel, in both post-Arabic alphabets (Latin and Cyrillic) of Azerbaijan.
In Romanian schwa is reprezented by letter Ă, ă, and it is a letter on its own (second in the Romanian alphabet). Unlike other languages (like English or French), it can be stressed in words were it is the only vowel such as "" (hair or pear tree) or "" (I see). Some words, which also contain other vowels, can have the stress on ă, like in the examples "" (the books) and "odăi" (rooms).
See main article: Schwa deletion in Indo-Aryan languages. Although the Devanagari script is used as a standard to write modern Hindi, the schwa (ə, sometimes written as a) implicit in each consonant of the script is "obligatorily deleted" at the end of words and in certain other contexts. This phenomenon has been termed the "schwa syncope rule" or the "schwa deletion rule" of Hindi. One formalization of this rule has been summarized as ə -> ø | VC_CV. In other words, when a vowel-preceded consonant is followed by a vowel-succeeded consonant, the schwa inherent in the first consonant is deleted. However, this formalization is inexact and incomplete (i.e. sometimes deletes a schwa when it shouldn't or, at other times, fails to delete it when it should), and can yield errors. Schwa deletion is computationally important because it is essential to building text-to-speech software for Hindi.
As a result of schwa syncope, the correct Hindi pronunciation of many words differs from that expected from a literal rendering of Devanagari. For instance, राम is Rām (incorrect: Rāma), रचना is Rachnā (incorrect: Rachanā), वेद is Véd (incorrect: Véda) and नमकीन is Namkeen (incorrect: Namakeena).
Correct schwa deletion is also critical because, in some cases, the same Devanagari letter-sequence is pronounced two different ways in Hindi depending on context, and failure to delete the appropriate schwas can change the sense of the word. For instance, the sequence धड़कने in दिल धड़कने लगा ("the heart started beating") and in दिल की धड़कनें ("beats of the heart") is identical prior to the nasalization in the second usage. Yet, it is pronounced dhadak.ne in the first and dhad.kane in the second. While native speakers correctly pronounce the sequence differently in different contexts, non-native speakers and voice-synthesis software can make them "sound very unnatural", making it "extremely difficult for the listener" to grasp the intended meaning.
American English has a tendency towards schwa deletion in medial posttonic syllables. Examples of this are sep(a)rate, choc(o)late, cam(e)ra and elab(o)rate, where the schwa (shown in parentheses) has a tendency to be deleted.
See main article: Laryngeal theory. The term "schwa" is also used for vowels of uncertain quality (rather than neutral sound) in the reconstructed Proto-Indo-European language. It was observed that, while for the most part a in Latin and Ancient Greek corresponds to a in Sanskrit, there are instances where Sanskrit has i while Latin and Greek have a, such as pitar (Sanskrit) vs pater (Latin and Ancient Greek). This postulated "schwa indogermanicum" evolved into the theory of the so-called laryngeals. Most scholars of Proto-Indo-European would now postulate three different phonemes rather than a single indistinct schwa. Some scholars postulate yet more, to explain further problems in the Proto-Indo-European vowel system. Most reconstructions of in older literature would correspond to *-h2- in contemporary notation.