Nunation (, '), in some Semitic languages such as Arabic, is the addition of one of three diacritics (cf. ḥarakÃÂt) to a noun or adjective in order to indicate that the word ends in a sequence of a vowel and an alveolar nasal. Thus, the presence of a consonant is exceptionally expressed without the addition of the corresponding letter (which otherwise normally would have been nà «n). The sequences marked by the diacritics represent case endings (nominative, accusative and genitive). The noun phrase is fully declinable and syntactically unmarked for definiteness, identifiable in speech.
When writing Literary Arabic in full diacritics, there are three nunation diacritics, which indicate the suffixes ' (IPA: /-un/) (nominative case), ' /-in/ (genitive), and ' /an/ (accusative). The orthographical rules for nunation with the sign is by an additional ' (, diacritic above alif; or , diacritic before alif; see below), above ( ) or above ( ).
In most dialects of spoken Arabic, nunation only exists in words and phrases borrowed from the literary language, especially those that are declined in the accusative (that is, with ). It is still used in some Bedouin dialects in its genitive form , such as in Najdi Arabic.
Since Arabic has no indefinite article, nouns that are nunated (except for proper nouns) are indefinite, and so the absence of the definite article triggers nunation in all nouns and substantives except diptotes (that is, derivations with only two cases in the indefinite state, -u in the nominative and -a in the accusative and genitive). A given name, if it is not a diptote, is also nunated when declined, as in (' "I bear witness that Muhammad is the messenger of Allah."), in which the word ', a given name derived from the passive participle of ("to praise"), is nunated to to signal that it is in the accusative case, as it is the grammatical subject of a sentence introduced by ("that").
<div style="padding: 0pt 3pt 0pt 3pt">
</div>
In Levantine Arabic, it is standard to write on the , rather than on the previous letter: <span style=font-size:160%;line-height:normal;"></span>
Xiao'erjing is a Perso-Arabic script adopted for writing of Sinitic languages such as Mandarin (especially the Lanyin, Zhongyuan and Northeastern dialects) or the Dungan language. This writing system is unique (compared to other Arabic-based writing systems) in that all vowels, long and short, are explicitly marked at all times with Arabic diacritics. In this script, the three nunations are used extensively to represent the alveolar (front) nasal sounds ("-n"), and also sometimes to represent velar (back) nasal sounds ("-ng"). <div style="padding: 0pt 3pt 0pt 3pt">
</div>
Nunation may also refer to the ' ending of duals in Akkadian (until it was dropped in the Old Babylonian period).