Lesson 21
Introduction to Diptotes
الممنوع من الصرف
Diptotes are nouns that never take tanwīn and use fatḥa instead of kasra in the genitive case. Recognising them prevents common case-marking errors throughout your Arabic study.
What Is a Diptote?
A diptote (مَمْنُوع مِنَ الصَّرْف = prevented from full declension) has only two case endings instead of three: it never takes tanwīn, and in the genitive case it takes fatḥa (not kasra). In the nominative and accusative, it behaves normally.
CaseNormal noun (كِتَاب)Diptote (مَسَاجِد)
Nominativeكِتَابٌمَسَاجِدُ
Accusativeكِتَاباًمَسَاجِدَ
Genitiveكِتَابٍمَسَاجِدَ (NOT مَسَاجِدٍ)
Main Diptote Categories
CategoryPatternExampleGenitive
Broken plural (4+ syllable)مَفَاعِل / فَعَالِلمَسَاجِدفِي مَسَاجِدَ
Colour/defect adj.أَفْعَلأَحْمَربِأَحْمَرَ
Feminine proper nounsends in ة or 3+ lettersفَاطِمَةلِفَاطِمَةَ
Foreign proper nounsnon-Arabic originإِبْرَاهِيملِإِبْرَاهِيمَ
ذَهَبَ إِلَى مَسَاجِدَ كَثِيرَةٍ فِي الْمَدِينَةِ مَرَّ بِإِبْرَاهِيمَ فِي السُّوقِ
Dhahaba ilā masājida kathīratin fī l-Madīna Marra bi-Ibrāhīma fī s-sūq
He went to many mosques in Madinah. He passed by Ibrahim in the market.
هَذِهِ الْمَسَاجِدُ قَدِيمَةٌ ذَهَبْتُ إِلَى الْمَسَاجِدِ (definite: reverts to kasra)
Hādhihi l-masājidu qadīmatun Dhahabtu ilā l-masājidi
These mosques are old. I went to the mosques. (definite article → normal kasra)
Sample Dialogue
أ: أَيْنَ ذَهَبَ إِبْرَاهِيمُ؟ ب: ذَهَبَ إِلَى مَسَاجِدَ فِي الْمَدِينَةِ. أ: وَهَلْ رَأَيْتَ فَاطِمَةَ؟ ب: نَعَمْ، رَأَيْتُهَا فِي الْمَدْرَسَةِ.
A: Ayna dhahaba Ibrāhīmu? B: Dhahaba ilā masājida fī l-Madīna. A: Wa-hal raʾayta Fāṭimata? B: Naʿam, raʾaytuhā fī l-madrasa.
A: Where did Ibrahim go? B: He went to mosques in Madinah. A: Did you see Fatima? B: Yes, I saw her in the school.
- Diptote: fatḥa in genitive where you would expect kasra, and no tanwīn ever.
- Exception: with definite article الـ or in iḍāfa (genitive construct), the diptote reverts to kasra.
- Key diptote categories to recognise: مَفَاعِل / فَعَالِل broken plurals; أَفْعَل colour/defect adjectives; proper nouns.
- Most foreign names (إِبْرَاهِيم، إِسْمَاعِيل، يُوسُف) are diptotes always use fatḥa in genitive.
- Practice: distinguish مِنْ مَسَاجِدَ (diptote genitive) vs مِنَ الْمَسَاجِدِ (definite, normal kasra).