Diakritik

Diacritics, or diakritik, are marks added to letters to modify their sound value, stress, or meaning. They occur in many writing systems, most prominently the Latin alphabet, but also in Greek, Arabic transliteration, and Vietnamese scripts. Diacritics can appear as combining marks or as part of a single precomposed character.

Common diacritics include the acute accent (á), grave accent (è), circumflex (â), tilde (ñ), diaeresis/umlaut (ï), cedilla (ç), caron/hacek (č), ring (̊) above letters such as å, and macron (ā). They indicate vowel quality, length, tone, or pronunciation and may distinguish minimal pairs or grammatical forms. In Vietnamese, diacritics determine tone and vowel quality with multiple marks on vowels.

In digital text, diacritics can appear as precomposed characters or combining marks. Unicode provides both, and normalization (NFC, NFD) ensures consistent representations. Diacritics affect search, sorting, text input, and accessibility; for example, Turkish i requires care with dotted and dotless forms.

Diacritics are essential for correct spelling in many languages; omission can change meaning or render text unreadable. They also pose challenges for typography, font design, rendering, and data interchange, especially for multilingual content and when switching between keyboards and input methods.