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).
For instance, in German where two words differ only by an umlaut, the word without it is sorted first in German dictionaries (e.g. In Spanish, the grapheme ñ is considered a new letter different from n and collated between n and o, as it denotes a different sound from that of a plain n.
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.
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.
In orthography and collation, a letter modified by a diacritic may be treated either as a new, distinct letter or as a letter–diacritic combination.
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.
The shape of the diacritic developed from initially resembling today's acute accent to a long flourish by the 15th century.
With the advent of Roman type it was reduced to the round dot we have today.