The Dual Changes Shape!

In Lesson 16.1, the Dual always ended in -aani (ـَانِ). But look at what happens when the Dual noun is placed after a preposition or in an Idafa — the ending changes!

Subject / Khabar (Marfoo')

الْكِتَابَانِ جَدِيدَانِ

Al-kitaabaani jadeedaani

The two books are new

Ending: ـَانِ (-aani)

After Preposition (Majroor)

فِي الْكِتَابَيْنِ

Fil-kitaabayni

In the two books

Ending: ـَيْنِ (-ayni)

The Rule: Two Forms of the Dual

Marfoo' (Subject)

ـَانِ

-aani

When the Dual is the subject or predicate

كِتَابَانِ

Majroor / Mansoob

ـَيْنِ

-ayni

After prepositions or as Mudhaf Ilayh

كِتَابَيْنِ

Examples — Both Forms in Context

Context	Arabic	Transliteration	Translation	Form Used
Subject	اَلْقَلَمَانِ جَدِيدَانِ	Al-qalamaani jadeedaani	The two pens are new	-aani ـَانِ
After فِي	فِي الْبَيْتَيْنِ	Fil-baytayni	In the two houses	-ayni ـَيْنِ
After مَعَ	مَعَ الطَّالِبَيْنِ	Ma'a al-taalibayni	With the two students	-ayni ـَيْنِ
Idafa (last)	كِتَابُ الطَّالِبَيْنِ	Kitaabu al-taalibayni	The book of the two students	-ayni ـَيْنِ
Subject	الْمَدْرَسَتَانِ كَبِيرَتَانِ	Al-madrasataani kabeerataani	The two schools are big	-aani ـَانِ

Drill — -aani or -ayni? Tap to reveal!

اَلْبَيْتَانِ
→ Marfoo': -aani (ـَانِ)

Subject: The two houses (are...)

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فِي الْبَيْتَيْنِ
→ Majroor: -ayni (ـَيْنِ)

After فِي: In the two houses

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اَلْوَلَدَانِ
→ Marfoo': -aani (ـَانِ)

Subject: The two boys (are...)

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مَعَ الْوَلَدَيْنِ
→ Majroor: -ayni (ـَيْنِ)

After مَعَ: With the two boys

Tap to reveal