Diacritics used with the Arabic alphabet:
Shaddah (Arabic: شَدّة shaddah [ˈʃæd.dæ], "[sign of] emphasis", also called by the verbal noun from the same root, tashdid تشديد tashdīd "emphasis") is one of the diacritics used with the Arabic alphabet, indicating a geminated consonant.
It is functionally equivalent to writing a consonant twice in the orthographies of languages like Latin, Italian, Swedish, and Ancient Greek, and is thus rendered in Latin script in most schemes of Arabic transliteration, e.g. رُمّان = rummān 'pomegranates'.
In shape, it is a small
letter س s(h)in, standing for shaddah.
It was devised for poetry by
al-Khalil ibn Ahmad in the eighth century, replacing an earlier dot.
When a shaddah is used on a
consonant which also takes a fatḥah /a/, the fatḥah is written above the
shaddah.
If the consonant takes a
kasrah /i/, it is written between the consonant and the shaddah instead of its
usual place below the consonant, however this last case is an exclusively
Arabic language practice, not in other languages that use the Arabic script.
When writing Arabic by hand,
it is customary first to write the shaddah and then the vowel diacritic.
In Unicode representation,
the shaddah can appear either before or after the vowel diacritic, and most
modern fonts can handle both options.
However, in the canonical
Unicode ordering the shaddah appears following the vowel diacritic, even though
phonetically it should follow directly the consonantal letter.
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