Diacritic is primarily an adjective, though sometimes used as a noun, whereas diacritical is only ever an adjective.
Some diacritical marks, such as the acute ( ´ ) and grave ( ` ), are often called accents.
Different languages use different rules to put diacritic characters in alphabetical order.
French treats letters with diacritical marks the same as the underlying letter for purposes of ordering and dictionaries.
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.
Examples are the diaereses in the borrowed French words naïve and Noël, which show that the vowel with the diaeresis mark is pronounced separately from the preceding vowel; the acute and grave accents, which can indicate that a final vowel is to be pronounced, as in saké and poetic breathèd; and the cedilla under the "c" in the borrowed French word façade, which shows it is pronounced .
In Gaelic type, a dot over a consonant indicates lenition of the consonant in question.
The j, originally a variant of i, inherited the tittle.This has led to fears internationally that the marks and accents may be made obsolete to facilitate the worldwide exchange of data.Efforts have been made to create internationalized domain names that further extend the English alphabet (e.g., "pokémon.com").They were written to the left of a syllable in vertical writing and above a syllable in horizontal writing.The South Korean government officially revised the romanization of the Korean language in July 2000 to eliminate diacritics.But the accented vowels á, é, í, ó, ú are not separated from the unaccented vowels a, e, i, o, u, as the acute accent in Spanish only modifies stress within the word or denotes a distinction between homonyms, and does not modify the sound of a letter.For a comprehensive list of the collating orders in various languages, see Collating sequence.Also, aa, when used as an alternative spelling to å, is sorted as such.Other letters modified by diacritics are treated as variants of the underlying letter, with the exception that ü is frequently sorted as y.In other alphabetic systems, diacritical marks may perform other functions.Vowel pointing systems, namely the Arabic harakat ( ), which, respectively, mark abbreviations or acronyms, and Greek diacritical marks, which showed that letters of the alphabet were being used as numerals.