The shape of the circumflex was originally a combination of the acute and grave accents (^), as it marked a syllablecontracted from two vowels: an acute-accented vowel and a non-accented vowel (all non-accented syllables in Ancient Greek were once marked with a grave accent). Later a variant similar to the tilde (~) was also used.
νόὺς = νoυ̂ς (νοῦς)
nóùs = noûs
The term[clarification needed] is also used to describe similar tonal accents that result from combining two vowels in related languages such as Sanskrit and Latin.
Akkadian. In the transliteration of this language, the circumflex indicates a long vowel resulting from an aleph contraction.
French. In some varieties, such as in Belgian French, Swiss French and Acadian French, vowels with a circumflex are long: fête [fɛːt] (party) is longer than faite [fɛt]. However, the circumflex originated as a sign of contraction (see below) in medieval manuscripts, not as a length sign.
In Serbo-Croatian the circumflex can be used to distinguish homographs, and it is called the "genitive sign" or "length sign". Examples include sam 'am' versus sâm 'alone'. For example, the phrase "I am alone" may be written Ja sam sâm to improve clarity. Another example: da 'yes', dâ 'gives'.
Turkish. According to Turkish Language Association orthography, düzeltme işareti 'correction mark' over a, i and u marks a long vowel to disambiguate similar words.For example, compare ama 'but' and âmâ 'blind', şura 'that place, there' and şûra 'council'. In general, circumflexes only occur in Arabic and Persianloanwords as vowel length in early Turkish was not phonemic. However, this standard was never applied entirely consistently and by the early 21st century many publications had stopped using circumflexes almost entirely.
Welsh. The circumflex is known as hirnod 'long sign', acen grom 'crooked accent' and also colloquially as to bach 'little roof'. It lengthens a vowel (a, e, i, o, u, w, y), and is used particularly to differentiate between homographs; e.g. tan and tân, ffon and ffôn, gem and gêm, cyn and cŷn, or gwn and gŵn.
The circumflex accent marks the stressed vowel of a word in some languages:
Portugueseâ, ê, and ô are stressed vowels. The circumflex further indicates their height (see below).
Welsh: the circumflex, due to its function as a disambiguating lengthening sign (see above), is used in polysyllabic words with word-final long vowels. The circumflex thus indicates the stressed syllable (which would normally be on the penultimate syllable), since in Welsh, non-stressed vowels may not normally be long. This happens notably where the singular ends in an a, to, e.g. singular camera, drama, opera, sinema → plural camerâu, dramâu, operâu, sinemâu; however, it also occurs in singular nominal forms, e.g. arwyddocâd; in verbal forms, e.g. deffrônt, cryffânt; etc.
In Afrikaans, circumflex simply marks a vowel with an irregular pronunciation that is typically stressed. Examples of circumflex use in Afrikaans are sê 'to say', wêreld 'world', môre 'tomorrow', and brûe 'bridges'.
In Breton, it is used on an e to show that the letter is pronounced open instead of closed.
In Bulgarian, when transliterated into the Latin alphabet (in systems used prior to 1989), the sound represented in Bulgarian by â, although called a schwa (misleadingly suggesting an unstressed lax sound), is more accurately described as a mid back unrounded vowel/ɤ/. Unlike English or French, but similar to Romanian and Afrikaans, it can be stressed. The Cyrillic letter ъ (er goljam) is sometimes transliterated as â or ŭ; often it is just written as a or u. (Though the list of unofficial transliterations for ъ does also include y and even 1.)
In Pinyin romanized Mandarin Chinese, ê is used to represent the sound /ɛ/ in isolation, which occurs sometimes as an exclamation.
in French, the letter ê is normally pronounced open, like è. In the usual pronunciations of central and northern France, ô is pronounced close, like eau; in Southern France, no distinction is made between close and openo.
Portugueseâ/ɐ/, ê/e/, and ô/o/ are stressed high vowels, in opposition to á/a/, é/ɛ/, and ó/ɔ/, which are stressed low vowels.
In Romanian, the circumflex is used on the vowels â and î to mark the vowel /ɨ/, similar to Russian yery. The names of these accented letters are â din a and î din i, respectively. (The letter â only appears in the middle of words; thus, its majuscule version appears only in all-capitals inscriptions.)
In Slovak, the circumflex (vokáň) turns the letter o into a diphthong: ô/uo/.
In Swedishdialect and folkloreliterature the circumflex is used to indicate the phonemes /a(ː)/ or /æ(ː)/(â), /ɶ(ː)/ or /ɞ(ː)/ (ô) and /ɵ(ː)/ (û) in dialects and regional accents where these are distinct from /ɑ(ː)/ (a), /ø(ː)/ (ö) or /o(ː)/ (o or å) and /ʉ(ː)/ (u) respectively, unlike Standard Swedish where [a] and [ɑː], [ɵ] and [ʉː] are short and long allophones of the phonemes /a/ and /ʉ/ respectively, and where Old Swedish short /o/ (ŏ) has merged with /o(ː)/ from Old Swedish /ɑː/ (ā, Modern Swedish å) instead of centralizing to [ɞ] or fronting to [ɶ] and remaining a distinct phoneme (ô) as in the dialects in question.
Vietnameseâ/ə/, ê/e/, and ô/o/ are higher vowels than a/ɑ/, e/ɛ/, and o/ɔ/. The circumflex can appear together with a tone mark on the same vowel, as in the word Việt Nam. Vowels with circumflex are considered separate letters from the base vowels.
In Turkish, the circumflex over a and u is sometimes used in words of Arabic or Persian derivation to indicate when a preceding consonant (k, g, l) is to be pronounced as a palatal plosive; [c], [ɟ] (kâğıt, gâvur, mahkûm, Gülgûn). The circumflex over i is used to indicate a nisba suffix (millî, dinî).
In the 18th century, the Real Academia Española introduced the circumflex accent in Spanish to mark that a ch or x were pronounced [k] and [ks] respectively (instead of [tʃ] and [x], which were the default values): châracteres, exâcto (spelled today caracteres, exacto). This usage was quickly abandoned during the same century, once the RAE decided to use ch and x with one assigned pronunciation only: [tʃ] and [ks] respectively.
Abbreviation, contraction, and disambiguation
In eighteenth-century British English, before the cheap Penny Post and during the time paper was taxed, the combination ough was shortened to ô when the gh was not pronounced, in order to save room in letters: thô for though, thorô for thorough, and brôt for brought.
In French, the circumflex generally marks the former presence of a consonant (usually s) that was deleted and is no longer pronounced. (The corresponding English words frequently retain the lost consonant.)
rôtir 'to roast'
dépôt (from the Latin depositum 'deposit', but now usually referring to a bus/rail terminal or garage)
Note that in current French, the English spellings, at least in terms of the syllable with the circumflex, could be pronounced the same as the French spellings, owing to the transformative effect of s on the preceding vowel – for example forêt[fɔʁɛ] 'forest', as per est[ɛ] 'is' (third person singular of être). Conversely, in the homographest[ɛst] 'east', the [s] sound is pronounced.
In handwritten French, for example in taking notes, an m with a circumflex (m̂) is an informal abbreviation for même 'same'.
In Italian, î is occasionally used in the plural of nouns and adjectives ending with -io[jo] as a crasis mark. Other possible spellings are -ii and obsolete -j or -ij. For example, the plural of vario[ˈvaːrjo] 'various' can be spelt vari, varî, varii; the pronunciation will usually stay [ˈvaːri] with only one [i]. The plural forms of principe[ˈprintʃipe] 'prince' and of principio[prinˈtʃipjo] 'principle, beginning' can be confusing. In pronunciation, they are distinguished by whether the stress is on the first or on the second syllable, but principi would be a correct spelling of both. When necessary to avoid ambiguity, it is advised to write the plural of principio as principî or as principii.
In Norwegian, the circumflex differentiates fôr 'lining, fodder' from the preposition for. From a historical point of view, the circumflex also indicates that the word used to be spelled with the letter ð in Old Norse – for example, fôr is derived from fóðr, lêr 'leather' from leðr, and vêr 'weather, ram' from veðr (both lêr and vêr only occur in the Nynorsk spelling; in Bokmål these words are spelled lær and vær). Before the ð disappeared, it was replaced by an ordinary d (fodr, vedr).
In mathematics, the circumflex is used to modify variable names; it is usually read "hat", e.g., î is "i hat". The Fourier transform of a function ƒ is often denoted by .
In the notation of sets, a hat above an element signifies that the element was removed from the set.
In statistics, the hat is used to denote an estimator or an estimated value, as opposed to its theoretical counterpart. For example, in errors and residuals, the hat in ε̂ indicates an observable estimate (the residuals) of an unobservable quantity called ε (the statistical errors). It is read x-hat or x-roof, where x represents the character under the hat.
For historical reasons, there is a similar but larger character, U+005E^circumflex accent, which is also included in ASCII but often referred to as caret instead. It is, however, unsuitable for use as a diacritic on modern computer systems, as it is a spacing character. Another spacing circumflex character in Unicode is the smaller U+02C6ˆmodifier letter circumflex, mainly used in phonetic notations – or as a sample of the diacritic in isolation.