Arabic

• (ئ ؤ إ أ and stand alone ء) hamza: indicates a glottal stop.
• (ــًــٍــٌـ) tanwīn (تنوين) symbols: Serve a grammatical role in Arabic. The sign ـً is most commonly written in combination with alif, e.g. ـًا.
• (ــّـ) shadda: Gemination (doubling) of consonants.
• (ٱ) waṣla: Comes most commonly at the beginning of a word. Indicates a type of hamza that is pronounced only when the letter is read at the beginning of the talk.
• (آ) madda: A written replacement for a hamza that is followed by an alif, i.e. (ءا). Read as a glottal stop followed by a long /aː/, e.g. ءاداب، ءاية، قرءان، مرءاة are written out respectively as آداب، آية، قرآن، مرآة. This writing rule does not apply when the alif that follows a hamza is not a part of the stem of the word, e.g. نتوءات is not written out as نتوآت as the stem نتوء does not have an alif that follows its hamza.
• (ــٰـ) superscript alif (also "short" or "dagger alif": A replacement for an original alif that is dropped in the writing out of some rare words, e.g. لاكن is not written out with the original alif found in the word pronunciation, instead it is written out as لٰكن.
• ḥarakāt (In Arabic: حركات also called تشكيل tashkīl):
  • (ــَـ) fatḥa (a)
  • (ــِـ) kasra (i)
  • (ــُـ) ḍamma (u)
  • (ــْـ) sukūn (no vowel)
• The ḥarakāt or vowel points serve two purposes:
  • They serve as a phonetic guide. They indicate the presence of short vowels (fatḥa, kasra, or ḍamma) or their absence (sukūn).
  • At the last letter of a word, the vowel point reflects the inflection case or conjugation mood.
    • For nouns, The ḍamma is for the nominative, fatḥa for the accusative, and kasra for the genitive.
    • For verbs, the ḍamma is for the imperfective, fatḥa for the perfective, and the sukūn is for verbs in the imperative or jussive moods.
• Vowel points or tashkīl should not be confused with consonant points or iʿjam (إعجام) – 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:

• ◌ͺ – iota subscript (ᾳ, εͅ, ῃ, ιͅ, οͅ, υͅ, ῳ)
• ῾◌ – rough breathing (Ancient Greek: δασὺ πνεῦμα, romanized: dasỳ pneûma, Latin: spīritus asper): aspiration
• ᾿◌ – smooth (or soft) breathing (Ancient Greek: ψιλὸν πνεῦμα, romanized: psilòn pneûma, Latin: spīritus lēnis): 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 (방점; 傍點), 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 [a], transliterated as a or ă,
• Two diagonally-placed dots above a letter represent [ɑ], transliterated as ā or â or å,
• Two horizontally-placed dots below a letter represent [ɛ], transliterated as e or ĕ; often pronounced [ɪ] and transliterated as i in the East Syriac dialect,
• Two diagonally-placed dots below a letter represent [e], transliterated as ē,
• A dot underneath the Beth represent a soft [v] sound, transliterated as v
• A tilde (~) placed under Gamel represent a [dʒ] sound, transliterated as j
• The letter Waw with a dot below it represents [u], transliterated as ū or u,
• The letter Waw with a dot above it represents [o], transliterated as ō or o,
• The letter Yōḏ with a dot beneath it represents [i], transliterated as ī or i,
• A tilde (~) under Kaph represent a [t͡ʃ] sound, transliterated as ch or č,
• A semicircle under Peh represents an [f] 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.^[4] Some transliteration schemes find its inclusion necessary for showing spirantization or for historical reasons.^[5][6]

Latin/Roman letters

Cyrillic letters

• Belarusian and Uzbek Cyrillic have a letter ў.
• Belarusian, Bulgarian, Russian and Ukrainian have the letter й.
• Belarusian and Russian have the letter ё. In Russian, this letter is usually replaced by е, although it has a different pronunciation. The use of е instead of ё does not affect the pronunciation. Ё is always used in children's books and in dictionaries. A minimal pair is все (vs'e, "everybody" pl.) and всё (vs'o, "everything" n. sg.). In Belarusian the replacement by е is a mistake; in Russian, it is permissible to use either е or ё for ё but the former is more common in everyday writing (as opposed to instructional or juvenile writing).
• The Cyrillic Ukrainian alphabet has the letters ґ, й and ї. Ukrainian Latynka has many more.
• Macedonian has the letters ќ and ѓ.
• In Bulgarian and Macedonian the possessive pronoun ѝ (ì, "her") is spelled with a grave accent in order to distinguish it from the conjunction и (i, "and").
• The acute accent  ́ above any vowel in Cyrillic alphabets is used in dictionaries, books for children and foreign learners to indicate the word stress, it also can be used for disambiguation of similarly spelled words with different lexical stresses.

English

English is one of the few European languages that does not have many words that contain diacritical marks. Instead, digraphs are the main way the Modern English alphabet adapts the Latin to its phonemes. Exceptions are unassimilated foreign loanwords, including borrowings from French (and, increasingly, Spanish, like jalapeño and piñata); however, the diacritic is also sometimes omitted from such words. Loanwords that frequently appear with the diacritic in English include café, résumé or resumé (a usage that helps distinguish it from the verb resume), soufflé, and naïveté (see English terms with diacritical marks). In older practice (and even among some orthographically-conservative modern writers), one may see examples such as élite, mêlée and rôle.

English speakers and writers once used the diaeresis more often than now in words such as coöperation (from Fr. coopération), zoölogy (from Grk. zoologia), and seeër (now more commonly see-er or simply seer) as a way of indicating that adjacent vowels belonged to separate syllables, but this practice has become far less common. The New Yorker magazine is a major publication that continues to use the diaeresis in place of a hyphen for clarity and economy of space.^[12]

A few English words, often when used out of context, especially in isolation, can only be distinguished from other words of the same spelling by using a diacritic or modified letter. These include exposé, lamé, maté, öre, øre, résumé and rosé. In a few words, diacritics that did not exist in the original have been added for disambiguation, as in maté (from Sp. and Port. mate), saké (the standard Romanization of the Japanese has no accent mark), and Malé (from Dhivehi މާލެ), to clearly distinguish them from the English words mate, sake, and male.

The acute and grave accents are occasionally used in poetry and lyrics: the acute to indicate stress overtly where it might be ambiguous (rébel vs. rebél) or nonstandard for metrical reasons (caléndar), the grave to indicate that an ordinarily silent or elided syllable is pronounced (warnèd, parlìament).

In certain personal names such as Renée and Zoë, often two spellings exist, and the person's own preference will be known only to those close to them. Even when the name of a person is spelled with a diacritic, like Charlotte Brontë, this may be dropped in English-language articles, and even in official documents such as passports, due either to carelessness, the typist not knowing how to enter letters with diacritical marks, or technical reasons (California, for example, does not allow^{[clarification needed]} names with diacritics, as the computer system cannot process such characters). They also appear in some worldwide company names and/or trademarks, such as Nestlé and Citroën.

Other languages

The following languages have letter-diacritic combinations that are not considered independent letters.

• Afrikaans uses a diaeresis to mark vowels that are pronounced separately and not as one would expect where they occur together, for example voel (to feel) as opposed to voël (bird). The circumflex is used in ê, î, ô and û generally to indicate long close-mid, as opposed to open-mid vowels, for example in the words wêreld (world) and môre (morning, tomorrow). The acute accent is used to add emphasis in the same way as underlining or writing in bold or italics in English, for example Dit is jóú boek (It is your book). The grave accent is used to distinguish between words that are different only in placement of the stress, for example appel (apple) and appèl (appeal) and in a few cases where it makes no difference to the pronunciation but distinguishes between homophones. The two most usual cases of the latter are in the sayings òf... òf (either... or) and nòg... nòg (neither... nor) to distinguish them from of (or) and nog (again, still).
• Aymara uses a diacritical horn over p, q, t, k, ch.
• Catalan has the following composite characters: à, ç, é, è, í, ï, ó, ò, ú, ü, l·l. The acute and the grave indicate stress and vowel height, the cedilla marks the result of a historical palatalization, the diaeresis indicates either a hiatus, or that the letter u is pronounced when the graphemes gü, qü are followed by e or i, the interpunct (·) distinguishes the different values of ll/l·l.
• Some orthographies of Cornish such as Kernowek Standard and Unified Cornish use diacritics, while others such as Kernewek Kemmyn and the Standard Written Form do not (or only use them optionally in teaching materials).
• Dutch uses the diaeresis. For example, in ruïne it means that the u and the i are separately pronounced in their usual way, and not in the way that the combination ui is normally pronounced. Thus it works as a separation sign and not as an indication for an alternative version of the i. Diacritics can be used for emphasis (érg koud for very cold) or for disambiguation between a number of words that are spelled the same when context does not indicate the correct meaning (één appel = one apple, een appel = an apple; vóórkomen = to occur, voorkómen = to prevent). Grave and acute accents are used on a very small number of words, mostly loanwords. The ç also appears in some loanwords.^[13]
• Faroese. Non-Faroese accented letters are not added to the Faroese alphabet. These include é, ö, ü, å and recently also letters like š, ł, and ć.
• Filipino has the following composite characters: á, à, â, é, è, ê, í, ì, î, ó, ò, ô, ú, ù, û. Everyday use of diacritics for Filipino is, however, uncommon, and meant only to distinguish between homonyms between a word with the usual penultimate stress and one with a different stress placement. This aids both comprehension and pronunciation if both are relatively adjacent in a text, or if a word is itself ambiguous in meaning. The letter ñ ("eñe") is not a n with a diacritic, but rather collated as a separate letter, one of eight borrowed from Spanish. Diacritics appear in Spanish loanwords and names observing Spanish orthography rules.
• Finnish. Carons in š and ž appear only in foreign proper names and loanwords, but may be substituted with sh or zh if and only if it is technically impossible to produce accented letters in the medium. Contrary to Estonian, š and ž are not considered distinct letters in Finnish.
• French uses five diacritics. The grave (accent grave) marks the sound /ɛ/ when over an e, as in père ("father") or is used to distinguish words that are otherwise homographs such as a/à ("has"/"to") or ou/où ("or"/"where"). The acute (accent aigu) is only used in "é", modifying the "e" to make the sound /e/, as in étoile ("star"). The circumflex (accent circonflexe) generally denotes that an S once followed the vowel in Old French or Latin, as in fête ("party"), the Old French being feste and the Latin being festum. Whether the circumflex modifies the vowel's pronunciation depends on the dialect and the vowel. The cedilla (cédille) indicates that a normally hard "c" (before the vowels "a", "o", and "u") is to be pronounced /s/, as in ça ("that"). The diaeresis diacritic (French: tréma) indicates that two adjacent vowels that would normally be pronounced as one are to be pronounced separately, as in Noël ("Christmas").
• Galician vowels can bear an acute (á, é, í, ó, ú) to indicate stress or difference between two otherwise same written words (é, 'is' vs. e, 'and'), but the diaeresis is only used with ï and ü to show two separate vowel sounds in pronunciation. Only in foreign words may Galician use other diacritics such as ç (common during the Middle Ages), ê, or à.
• German uses the three umlauted characters ä, ö and ü. These diacritics indicate vowel changes. For instance, the word Ofen [ˈoːfən] "oven" has the plural Öfen [ˈøːfən]. The mark originated as a superscript e; a handwritten blackletter e resembles two parallel vertical lines, like a diaeresis. Due to this history, "ä", "ö" and "ü" can be written as "ae", "oe" and "ue" respectively, if the umlaut letters are not available.
• Hebrew has many various diacritic marks known as niqqud that are used above and below script to represent vowels. These must be distinguished from cantillation, which are keys to pronunciation and syntax.
• The International Phonetic Alphabet uses diacritic symbols and characters to indicate phonetic features or secondary articulations.
• Irish uses the acute to indicate that a vowel is long: á, é, í, ó, ú. It is known as síneadh fada "long sign" or simply fada "long" in Irish. In the older Gaelic type, overdots are used to indicate lenition of a consonant: ḃ, ċ, ḋ, ḟ, ġ, ṁ, ṗ, ṡ, ṫ.
• Italian mainly has the acute and the grave (à, è/é, ì, ò/ó, ù), typically to indicate a stressed syllable that would not be stressed under the normal rules of pronunciation but sometimes also to distinguish between words that are otherwise spelled the same way (e.g. "e", and; "è", is). Despite its rare use, Italian orthography allows the circumflex (î) too, in two cases: it can be found in old literary context (roughly up to 19th century) to signal a syncope (fêro→fecero, they did), or in modern Italian to signal the contraction of ″-ii″ due to the plural ending -i whereas the root ends with another -i; e.g., s. demonio, p. demonii→demonî; in this case the circumflex also signals that the word intended is not demoni, plural of "demone" by shifting the accent (demònî, "devils"; dèmoni, "demons").
• Lithuanian uses the acute, grave and tilde in dictionaries to indicate stress types in the language's pitch accent system.
• Maltese also uses the grave on its vowels to indicate stress at the end of a word with two syllables or more:– lowercase letters: à, è, ì, ò, ù; capital letters: À, È, Ì, Ò, Ù
• Māori makes use of macrons to mark long vowels.
• Occitan has the following composite characters: á, à, ç, é, è, í, ï, ó, ò, ú, ü, n·h, s·h. The acute and the grave indicate stress and vowel height, the cedilla marks the result of a historical palatalization, the diaeresis indicates either a hiatus, or that the letter u is pronounced when the graphemes gü, qü are followed by e or i, and the interpunct (·) distinguishes the different values of nh/n·h and sh/s·h (i.e., that the letters are supposed to be pronounced separately, not combined into "ny" and "sh").
• Portuguese has the following composite characters: à, á, â, ã, ç, é, ê, í, ó, ô, õ, ú. The acute and the circumflex indicate stress and vowel height, the grave indicates crasis, the tilde represents nasalization, and the cedilla marks the result of a historical lenition.
• Acutes are also used in Slavic language dictionaries and textbooks to indicate lexical stress, placed over the vowel of the stressed syllable. This can also serve to disambiguate meaning (e.g., in Russian писа́ть (pisáť) means "to write", but пи́сать (písať) means "to piss"), or "бо́льшая часть" (the biggest part) vs "больша́я часть" (the big part).
• Spanish uses the acute and the diaeresis. The acute is used on a vowel in a stressed syllable in words with irregular stress patterns. It can also be used to "break up" a diphthong as in tío (pronounced [ˈti.o], rather than [ˈtjo] as it would be without the accent). Moreover, the acute can be used to distinguish words that otherwise are spelled alike, such as si ("if") and sí ("yes"), and also to distinguish interrogative and exclamatory pronouns from homophones with a different grammatical function, such as donde/¿dónde? ("where"/"where?") or como/¿cómo? ("as"/"how?"). The acute may also be used to avoid typographical ambiguity, as in 1 ó 2 ("1 or 2"; without the acute this might be interpreted as "1 0 2". The diaeresis is used only over u (ü) for it to be pronounced [w] in the combinations gue and gui, where u is normally silent, for example ambigüedad. In poetry, the diaeresis may be used on i and u as a way to force a hiatus. As foreshadowed above, in nasal ñ the tilde (squiggle) is not considered a diacritic sign at all, but a composite part of a distinct glyph, with its own chapter in the dictionary: a glyph that denotes the 15th letter of the Spanish alphabet.
• Swedish uses the acute to show non-standard stress, for example in kafé (café) and resumé (résumé). This occasionally helps resolve ambiguities, such as ide (hibernation) versus idé (idea). In these words, the acute is not optional. Some proper names use non-standard diacritics, such as Carolina Klüft and Staël von Holstein. For foreign loanwords the original accents are strongly recommended, unless the word has been infused into the language, in which case they are optional. Hence crème fraîche but ampere. Swedish also has the letters å, ä, and ö, but these are considered distinct letters, not a and o with diacritics.
• Tamil does not have any diacritics in itself, but uses the Arabic numerals 2, 3 and 4 as diacritics to represent aspirated, voiced, and voiced-aspirated consonants when Tamil script is used to write long passages in Sanskrit.
• Thai has its own system of diacritics derived from Indian numerals, which denote different tones.
• Vietnamese uses the acute (dấu sắc), the grave (dấu huyền), the tilde (dấu ngã), the underdot (dấu nặng) and the hook above (dấu hỏi) on vowels as tone indicators.
• Welsh uses the circumflex, diaeresis, acute, and grave on its seven vowels a, e, i, o, u, w, y. The most common is the circumflex (which it calls to bach, meaning "little roof", or acen grom "crooked accent", or hirnod "long sign") to denote a long vowel, usually to disambiguate it from a similar word with a short vowel or a semivowel. The rarer grave accent has the opposite effect, shortening vowel sounds that would usually be pronounced long. The acute accent and diaeresis are also occasionally used, to denote stress and vowel separation respectively. The w-circumflex ŵ and the y-circumflex ŷ are among the most commonly accented characters in Welsh, but unusual in languages generally, and were until recently very hard to obtain in word-processed and HTML documents.

Orthographic

Possibly the greatest number of combining diacritics required to compose a valid character in any Unicode language is 8, for the "well-known grapheme cluster in Tibetan and Ranjana scripts" or HAKṢHMALAWARAYAṀ.^[14]

It consists of

1. U+0F67 ཧ TIBETAN LETTER HA
2. U+0F90 ྐ TIBETAN SUBJOINED LETTER KA
3. U+0FB5 ྵ TIBETAN SUBJOINED LETTER SSA
4. U+0FA8 ྨ TIBETAN SUBJOINED LETTER MA
5. U+0FB3 ླ TIBETAN SUBJOINED LETTER LA
6. U+0FBA ྺ TIBETAN SUBJOINED LETTER FIXED-FORM WA
7. U+0FBC ྼ TIBETAN SUBJOINED LETTER FIXED-FORM RA
8. U+0FBB ྻ TIBETAN SUBJOINED LETTER FIXED-FORM YA
9. U+0F82 ྂ TIBETAN SIGN NYI ZLA NAA DA

An example of rendering, may be broken depending on browser:

ཧྐྵྨླྺྼྻྂ

Unorthographic/ornamental

Some users have explored the limits of rendering in web browsers and other software by "decorating" words with excessive nonsensical diacritics per character to produce so-called Zalgo text.