Common (and a few not-so-common) diacriticals used with the Latin alphabet:
- Acute (as in á). In many languages, used to mark primary accent when it falls in a nonstandard place. In others, often used to change the quality of a vowel (by making it fronter, for example), or to make it longer. In a few languages, used to palatalise certain consonants.
- Grave (as in à). In many languages, used to change the quality of a vowel. Used in English poetry to indcate that a vowel which would normally be unstressed is being stressed for reasons of metre.
- Umlaut (as in ü). In many languages, used to apply the umlaut translation, which make back vowels (like `a', `o', `u') fronter.
- Diaeresis (as in ië). In many languages, used to indicate that two vowels are to be pronounced separately, rather than as a diphthong. In Dutch, for example, `ie' is pronounced /i:/, while `ië' is pronounced /i @/ (where @ is schwa). Diaeresis is written the same as umlaut, but is really a different diacritical.
- Double acute. Used in Hungarian to represent a long umlauted vowel.
- Macron. Used to indicate long vowels. In phonetic transcriptions of some languages (English, for example), indicates a change in vowel quality. For example, a-macron in English phonetics is really an umlauted a, while i-macron becomes a back-to-front diphthong. So-called `long vowels' in English are no longer long forms of the corresponding short vowels, thanks to the Great Vowel Shift.
- Ring (as in å). Used in some North Germanic (Scandinavian) languages to change the quality of the letter `a'. Technically, `å' is a completely different character, so `diacritical' is perhaps not a good word here.
- Circumflex (as in ê). Often used in French to indicate a vowel etymologically followed by an `s', but where the `s' had been dropped. For example, `bête', `hôte'. May also change vowel quality.
- Caron (inverted circumflex). Used in some Eastern European languages to indicate palatalisation of a consonant. Often called `hacek', from the Czech.
- Breve (concave-up curve). Used in phonetic descriptions to indicate short vowels.
- Tilde (ã). Used in many languages to indicate nasalised vowels. Used in some languages to indicate palatalised `n'.
- Cedilla (ç). Used in many languages to indicate that a vowel is palatalised or otherwise soft.
- Ogonek (like a backwards cedilla, on the lower-right of a character). Used in Polish on the letters `a' and `e' to change their quality and nasalise them.
- Dot above. Used over the letter `z' in Polish to hard-palatalise it (as opposed to the soft-palatalised z with acute)
- Slash (as in ø). Used to change the quality of the letter `o' in some Scandinavian languages. Like `å', `ø' is really a distinct character rather than a character with a diacritical.
- Bar. Used through the letter `l' in Polish to change its pronunciation from /l/ to /w/. L-bar (I can't remember the Polish for it at the moment) is considered a completely different letter.