Modern computer technology was developed mostly in English-speaking countries, so data formats, keyboard layouts, etc.
Diacritical marks 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 diacritical marks in the Latin script is to change the sound-values of the letters to which they are added.
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".
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. 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.Depending on the keyboard layout, which differs amongst countries, it is more or less easy to enter letters with diacritics on computers and typewriters.Some have their own keys; some are created by first pressing the key with the diacritic mark followed by the letter to place it on.Languages that treat accented letters as variants of the underlying letter usually alphabetize words with such symbols immediately after similar unmarked words. in phone books or in author catalogues in libraries), umlauts are often treated as combinations of the vowel with a suffixed e; Austrian phone books now treat characters with umlauts as separate letters (immediately following the underlying vowel).