A diacritic (also diacritical mark, diacritical point, diacritical sign, or accent) is a glyph added to a letter or to a basic glyph. The term derives from the Ancient Greek (, "distinguishing"), from (, "to distinguish"). The word diacritic is a noun, though it is sometimes used in an attributive sense, whereas diacritical is only an adjective. Some diacritics, such as the acute , grave , and circumflex (all shown above an 'o'), are often called accents. Diacritics may appear above or below a letter or in some other position such as within the letter or between two letters.
The main use of diacritics in Latin script is to change the sound-values of the letters to which they are added. Historically, English has used the diaeresis diacritic to indicate the correct pronunciation of ambiguous words, such as "coöperate", without which the <oo> letter sequence could be misinterpreted to be pronounced . Other examples are the acute and grave accents, which can indicate that a vowel is to be pronounced differently from what is normal in that position, for example not reduced to /ə/ or silent as in the case of the two uses of the letter e in the noun résumé (as opposed to the verb resume) and the help sometimes provided in the pronunciation of some words such as doggèd, learnèd, blessèd, and especially words pronounced differently than normal in poetry (for example movèd, breathèd).
Most other words with diacritics in English are borrowings from languages such as French to better preserve the spelling, such as the diaeresis on and , the acute from , the circumflex in the word , and the cedille in . All these diacritics, however, are frequently omitted in writing, and English is the only major modern European language that does not have diacritics in common usage.
In Latin-script alphabets in other languages diacritics may distinguish between homonyms, such as the French ("there") versus ("the"), which are both pronounced . In Gaelic type, a dot over a consonant indicates lenition of the consonant in question. In other writing systems, diacritics may perform other functions. Vowel pointing systems, namely the Arabic harakat and the Hebrew niqqud systems, indicate vowels that are not conveyed by the basic alphabet. The Indic virama ( ् etc.) and the Arabic sukūn ( ) mark the absence of vowels. Cantillation marks indicate prosody. Other uses include the Early Cyrillic titlo stroke ( ◌҃ ) and the Hebrew gershayim ( ), which, respectively, mark abbreviations or acronyms, and Greek diacritical marks, which showed that letters of the alphabet were being used as numerals. In Vietnamese and the Hanyu Pinyin official romanization system for Mandarin in China, diacritics are used to mark the tones of the syllables in which the marked vowels occur.
In orthography and collation, a letter modified by a diacritic may be treated either as a new, distinct letter or as a letter–diacritic combination. This varies from language to language and may vary from case to case within a language.
In some cases, letters are used as "in-line diacritics", with the same function as ancillary glyphs, in that they modify the sound of the letter preceding them, as in the case of the "h" in the English pronunciation of "sh" and "th". Such letter combinations are sometimes even collated as a single distinct letter. For example, the spelling sch was traditionally often treated as a separate letter in German. Words with that spelling were listed after all other words spelled with s in card catalogs in the Vienna public libraries, for example (before digitization).
Types
Among the types of diacritic used in alphabets based on the Latin script are: accents (so called because the acute, grave, and circumflex were originally used to indicate different types of pitch accents in the polytonic transcription of Greek)
– acute (); for example – grave; for example – circumflex; for example – caron, wedge; for example – double acute; for example – double grave; for example
one dot – an overdot is used in many orthographies and transcriptions; for example – an underdot is also used in many orthographies and transcriptions; for example – an interpunct is used in the Catalan (l·l) – a dot above right is used in Pe̍h-ōe-jī tittle, the superscript dot of the modern lowercase Latin and two dots: two overdots () are used for umlaut, diaeresis and others; (for example ) two underdots () are used in the International Phonetic Alphabet (IPA) and the ALA-LC romanization system – triangular colon, used in the IPA to mark long vowels (the "dots" are triangular, not circular). curves – breve; for example – inverted breve; for example – sicilicus, a palaeographic diacritic similar to a caron or breve – tilde; for example – titlo vertical stroke – a subscript vertical stroke is used in IPA to mark syllabicity and in to mark a schwa – a superscript vertical stroke is used in Pe̍h-ōe-jī macron or horizontal line – macron; for example – underbar overlays – vertical bar through the character – slash through the character; for example – crossbar through the character ring – overring: for example superscript curls – comma above – inverted apostrophe – reversed comma above – hook above (); for example – horn (); for example subscript curls – undercomma; for example – cedilla; for example – hook, left or right, sometimes superscript – ogonek; for example double marks (over or under two base characters) – double breve – tie bar or top ligature – double circumflex – longum – double tilde double sub/superscript diacritics – double cedilla – double ogonek – double diaeresis – double ypogegrammeni
The tilde, dot, comma, titlo, apostrophe, bar, and colon are sometimes diacritical marks, but also have other uses.
Not all diacritics occur adjacent to the letter they modify. In the Wali language of Ghana, for example, an apostrophe indicates a change of vowel quality, but occurs at the beginning of the word, as in the dialects ’Bulengee and ’Dolimi. Because of vowel harmony, all vowels in a word are affected, so the scope of the diacritic is the entire word. In abugida scripts, like those used to write Hindi and Thai, diacritics indicate vowels, and may occur above, below, before, after, or around the consonant letter they modify.
The tittle (dot) on the letter or the letter , of the Latin alphabet originated as a diacritic to clearly distinguish from the minims (downstrokes) of adjacent letters. It first appeared in the 11th century in the sequence ii (as in ), then spread to i adjacent to m, n, u, and finally to all lowercase is. The , originally a variant of i, inherited the tittle. The shape of the diacritic developed from initially resembling today's acute accent to a long flourish by the 15th century. With the advent of Roman type it was reduced to the round dot we have today.Oxford English Dictionary
Several languages of eastern Europe use diacritics on both consonants and vowels, whereas in western Europe digraphs are more often used to change consonant sounds. Most languages in Europe use diacritics on vowels, aside from English where there are typically none (with some exceptions).
Diacritics specific to non-Latin alphabets
Arabic
(ئ ؤ إ أ and stand alone ء) : indicates a glottal stop. (ــًــٍــٌـ) () symbols: Serve a grammatical role in Arabic. The sign ـً is most commonly written in combination with alif, e.g. . (ــّـ) : Gemination (doubling) of consonants. (ٱ) : Comes most commonly at the beginning of a word. Indicates a type of that is pronounced only when the letter is read at the beginning of the talk. (آ) : A written replacement for a that is followed by an alif, i.e. (). Read as a glottal stop followed by a long , e.g. are written out respectively as . This writing rule does not apply when the alif that follows a is not a part of the stem of the word, e.g. is not written out as as the stem does not have an alif that follows its . (ــٰـ) superscript (also "short" or "dagger alif": A replacement for an original alif that is dropped in the writing out of some rare words, e.g. is not written out with the original alif found in the word pronunciation, instead it is written out as . (In Arabic: also called ): (ــَـ) (a) (ــِـ) (i) (ــُـ) (u) (ــْـ) (no vowel) The or vowel points serve two purposes: They serve as a phonetic guide. They indicate the presence of short vowels (, , or ) or their absence (). At the last letter of a word, the vowel point reflects the inflection case or conjugation mood. For nouns, The is for the nominative, for the accusative, and for the genitive. For verbs, the is for the imperfective, for the perfective, and the is for verbs in the imperative or jussive moods. Vowel points or should not be confused with consonant points or () – one, two or three dots written above or below a consonant to distinguish between letters of the same or similar form.
Greek
These diacritics are used in addition to the acute, grave, and circumflex accents and the diaeresis: – iota subscript () – rough breathing (, ): aspiration – smooth (or soft) breathing (, ): lack of aspiration
Hebrew
Niqqud – Dagesh – Mappiq – Rafe – Shin dot (at top right corner) – Sin dot (at top left corner) – Shva – Kubutz – Holam – Kamatz – Patakh – Segol – Tzeire – Hiriq
(Cantillation marks do not generally render correctly; refer to Hebrew cantillation#Names and shapes of the ta'amim for a complete table together with instructions for how to maximize the possibility of viewing them in a web browser.) Other – Geresh – Gershayim
Korean
The diacritics 〮 and 〯 , known as Bangjeom (), were used to mark pitch accents in Hangul for Middle Korean. They were written to the left of a syllable in vertical writing and above a syllable in horizontal writing.
Sanskrit and Indic
Syriac
A dot above and a dot below a letter represent , transliterated as a or ă, Two diagonally-placed dots above a letter represent , transliterated as ā or â or å, Two horizontally-placed dots below a letter represent , transliterated as e or ĕ; often pronounced and transliterated as i in the East Syriac dialect, Two diagonally-placed dots below a letter represent , transliterated as ē, A dot underneath the Beth represent a soft sound, transliterated as v A tilde (~) placed under Gamel represent a sound, transliterated as j The letter Waw with a dot below it represents , transliterated as ū or u, The letter Waw with a dot above it represents , transliterated as ō or o, The letter Yōḏ with a dot beneath it represents , transliterated as ī or i, A tilde (~) under Kaph represent a sound, transliterated as ch or č, A semicircle under Peh represents an sound, transliterated as f or ph.
In addition to the above vowel marks, transliteration of Syriac sometimes includes ə, e̊ or superscript e (or often nothing at all) to represent an original Aramaic schwa that became lost later on at some point in the development of Syriac.Nestle, Eberhard (1888). Syrische Grammatik mit Litteratur, Chrestomathie und Glossar. Berlin: H. Reuther's Verlagsbuchhandlung. [translated to English as Syriac grammar with bibliography, chrestomathy and glossary, by R. S. Kennedy. London: Williams & Norgate 1889]. Some transliteration schemes find its inclusion necessary for showing spirantization or for historical reasons.Coakley, J. F. (2002). Robinson's Paradigms and Exercises in Syriac Grammar (5th ed.). Oxford University Press. .Michaelis, Ioannis Davidis (1784). Grammatica Syriaca.
Non-alphabetic scripts Some non-alphabetic scripts also employ symbols that function essentially as diacritics.