The shape of the circumflex was originally a combination of the acute and grave accents (^), as it marked a syllable contracted 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.
In Afrikaans, the circumflex marks a vowel with a lengthened pronunciation, often arising from compensatory lengthening due to the loss of ⟨g⟩ from the original Dutch form. Examples of circumflex use in Afrikaans are sê "to say", wêreld "world", môre "tomorrow", brûe "bridges".
Akkadian. In the transliteration of this language, the circumflex indicates a long vowel resulting from an aleph contraction.
The PDA orthography for Domari uses circumflex-bearing vowels for length.
In Emilian, â î û are used to represent [a:, i:, u:]
In Luxembourgishm? n? can be used to indicate nasalisation of a vowel. Also, the circumflex can be over the vowel to indicate nasalisation. In either case, the circumflex is rare.
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 i?areti "correction mark" over a, i and u marks a long vowel to disambiguate similar words. For example, compare ama "but" and âmâ "blind", ?ura 'that place, there' and ?ûra "council". In general, circumflexes occur only 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" or acen grom "crooked accent", but more usually and colloquially as to bach "little roof". It lengthens a stressed 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 c?n, or gwn and g?n.
Bilingual sign showing the use of the circumflex in Welsh as an indicator of length and stress: parêd [pa're:d] "parade", as opposed to pared ['par?d] "partition wall".
The circumflex accent marks the stressed vowel of a word in some languages:
Portugueseâ, ê, and ô are stressed "closed" vowels, opposed to their open counterparts á, é, and ó (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 Bamanankan, it marks a falling tone, as opposed to a há?ek which signifies that on this syllable, the tone is rising.
In Breton, it is used on an e to show that the letter is pronounced open instead of closed.
In Bulgarian, the sound represented in Bulgarian by the Cyrillic letter ? (er goljam) is usually transliterated as â in systems used prior to 1989. Although called a schwa (misleadingly suggesting an unstressed lax sound), it is more accurately described as a mid back unrounded vowel/?/. Unlike English or French, but similar to Romanian and Afrikaans, it can be stressed.
In Pinyin romanized Mandarin Chinese, ê is used to represent the sound /?/ 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/?/, ê/e/, and ô/o/ are stressed high vowels, in opposition to á/a/, é/?/, and ó/?/, which are stressed low vowels.
In Romanian, the circumflex is used on the vowels â and î to mark the vowel /?/, 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 (voká?) turns the letter o into a diphthong: ô/uo/.
In Swedishdialect and folkloreliterature the circumflex is used to indicate the phonemes /a(:)/ or /æ(:)/(â), /?(:)/ or /?(:)/ (ô) and /?(:)/ (û) in dialects and regional accents where these are distinct from /?(:)/ (a), /ø(:)/ (ö) or /o(:)/ (o or å) and /?(:)/ (u) respectively, unlike Standard Swedish where [a] and [?:], [?] and [?:] are short and long allophones of the phonemes /a/ and /?/ respectively, and where Old Swedish short /o/ (?) has merged with /o(:)/ from Old Swedish /?:/ (?, Modern Swedish å) instead of centralizing to [?] or fronting to [?] and remaining a distinct phoneme (ô) as in the dialects in question. Different methods can be found in different literature, so some author may use æ instead of â, or use â where others use å? (å with a circumflex; for a sound between /?(:)/ and /o(:)/).
Vietnameseâ/?/, ê/e/, and ô/o/ are higher vowels than a/?/, e/?/, and o/?/. The circumflex can appear together with a tone mark on the same vowel, as in the word Vi?t. Vowels with circumflex are considered separate letters from the base vowels.
Other articulatory features
In Emilian, ê ô [e:, o:] denote both length and height. In Romagnol, they are used to represent the diphthongs /e?, o?/, whose specific articulation varies between dialects, e.g. sêl [se?l~se?l~sæ?l~sl] "salt".
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], [?] (kât, gâvur, mahkûm, Gülgûn). The circumflex over i is used to indicate a nisba suffix (millî, dinî).
In the African language Venda, a circumflex below d, l, n, and t is used to represent dental consonants, ?, ?, ?.
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 [t?] 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: [t?] and [ks] respectively.
In Domari (according to the Pan-Domari Alphabet orthography), the circumflex is used on the letters <? ? ? ? ?> to represent the sounds of /t ? d ? ?/.
Abbreviation, contraction, and disambiguation
In 18th century British English, before the cheap Penny Post and while paper was taxed, the combination ough was occasionally shortened to ô when the gh was not pronounced, to save space: 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 Norman French words, and consequently the words derived from them in English, frequently retain the lost consonant.) For example:
rôtir "to roast"
dépôt (from the Latin depositum 'deposit', but now referring to both a deposit or a storehouse of any kind)
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[clarification needed] – for example forêt[f] "forest", as per est[?] "is" (third person singular of être). Conversely, in the homographest[?st] "east", the [s] sound is pronounced.
Some homophones (or near-homophones in some varieties of French) are distinguished by the circumflex. However, â, ê and ô distinguish different sounds in most varieties of French, for instance cote[k?t] "level, mark, code number" and côte[kot] "rib, coast, hillside".
In handwritten French, for example in taking notes, an m with a circumflex (m?) is an informal abbreviation for même "same".
In February 2016, the Académie française decided to remove the circumflex from about 2000 words, a plan that had been outlined since 1990. However, usage of the circumflex would not be considered incorrect.
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['va:rjo] "various" can be spelt vari, varî, varii; the pronunciation will usually stay ['va:ri] with only one [i]. The plural forms of principe['print?ipe] "prince" and of principio[prin't?ipjo] "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). After the ð disappeared, it was replaced by a 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 ? is often denoted by .
In the notation of sets, a hat above an element signifies that the element was removed from the set, such as in , the set containing all elements except .
In geometry, a hat is sometimes used for an angle. For instance, the angles or .
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 indicates an observable estimate (the residual) of an unobservable quantity called (the statistical error). It is read x-hat or x-roof, where x represents the character under the hat.
The Unicode code point for the circumflex is ^CIRCUMFLEX (HTML ^) (^ in HTML5).
The precomposed charactersÂ/â, Ê/ê, Î/î, Ô/ô, and Û/û (which incorporate the circumflex) are included in the ISO-8859-1 character set, and dozens more are available in Unicode. In addition, Unicode has ◌̂COMBINING CIRCUMFLEX ACCENT and ◌̭COMBINING CIRCUMFLEX ACCENT BELOW which in principle allow adding the diacritic to any base letter.
For historical reasons, there is a similar but larger character, ^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 ˆMODIFIER LETTER CIRCUMFLEX ACCENT, mainly used in phonetic notations – or as a sample of the diacritic in isolation.
^ Weisstein, Eric W. "Hat". Mathworld. Wolfram. Retrieved 2016.
^Herbert Weir Smyth, A Greek Grammar for Colleges (ccel.org): "155. The ancients regarded the grave originally as belonging to every syllable not accented with the acute or circumflex; and some Mss. show this in practice, e.g. . [...]"