Most Arabic nouns are fully flexible: they can take tanween (the doubled vowel at the end of indefinite words) and use a kasra in the genitive case (such as after a preposition).
However, a special category of words known as diptotes (الممنوع من الصرف) breaks these rules in two ways:
- They never take tanween.
- In the genitive case, they take a fatha instead of a kasra.
Foreign Names and Cities
Names of non-Arabic origin and almost all names of cities, countries, and towns are diptotes. Following a preposition like إلى (to) or من (from), they take a fatha instead of a kasra.
| Ibrahim traveled to Paris. | سافر إبراهيم إلى باريس.sâfara ibrâhîmu ilâ bârîs |
| They returned from Damascus to Baghdad. | رجعوا من دمشق إلى بغداد.rajaʿū min dimashqa ilâ baghdâda |
Notice how cities like باريس and دمشق, as well as the name إبراهيم, do not take tanween. In addition, the cities end with a fatha despite following prepositions.
Feminine Names and Specific Patterns
All feminine personal names are diptotes, whether they end in a taa marbuta (like فاطمة) or not (like مريم).
| Fatima was a nurse in London. | كانت فاطمة ممرضة في لندن.kânat fâtimatu mumarridatan fî landana. |
| Maryam and Fatima went to London. | ذهبت مريم وفاطمة إلى لندن.dhahabat maryamu wa fâtimatu ilâ landana. |
Some Arabic male names also belong to this category if they mimic the shape of a verb (like أحمد). Many historical names (like يوسف) are also diptotes due to their foreign origin.
| Ahmad was happy in Mecca. | كان أحمد سعيدا في مكة.kâna aḥmadu sa'îdan fî makkata |
| Yusuf and Ahmad traveled to Paris. | سافر يوسف وأحمد إلى باريس.sâfara yûsufu wa ahmadu ilâ bârîsa |