shadda

Shadda, also called shaddah, is a diacritic in the Arabic script used to indicate consonant gemination, or doubling. It appears as a small, curved sign placed above the affected letter and is one of the marks used to guide pronunciation in Arabic orthography.

When a shadda accompanies a short-vowel sign such as fatha, damma, or kasra, the vowel is associated with the first of the two identical consonants; the consonant is pronounced twice with that vowel on the first instance. In other cases, the consonant is simply pronounced longer. In unvoweled text, readers rely on morphology and context to determine pronunciation and syllable structure. The shadda is important for preserving morphology, as many Arabic verb patterns and noun forms depend on gemination.

Usage is common in Arabic and in other languages that use the Arabic script, including Urdu, Persian, Kurdish, and others, where the mark serves the same gemination function. It is encoded as a combining character in digital text, separate from the base letter. In Unicode, the diacritic is U+0651 ARABIC SHADDA. In printed Qur’anic and traditional texts, shadda helps reflect proper pronunciation and morphological patterns; in everyday modern Arabic, diacritics are often omitted, and readers supply vowels and gemination from context.

Example: the verb root d-r-s can appear as دَرَّسَ, with a shadda on the second letter to indicate doubling, meaning “to teach (someone).” Another form is مَدَّ, where the shadda marks gemination on the second consonant.