Arabic has a separate form to show the number ‘two’. To convert a single-noun to dual or muthannā, ‘āni’ is added for nominal, and ‘ayni for genitive and accusative cases.
قَلَمٌ pen ← قَلَمَانِ / قَلَمَينِ two pens
وَلَدٌ boy ← وَلَدَانِ / وَلَدَينِ two boys
كِتَابٌ book ← كِتَابَانِ / كِتَابَينِ two books
More examples:
هَذَينِ كِتَابَينِ
These two books
رفَعَ الوَلَدُ يَدَيهِ
The boy raised his two hands
مُحَمَّدٌ وَأَحمَدُ سَيُغَادِرَانِ غَدًا إن شاء الله
Muhammad and Ahmad will leave tomorrow, insha’ Allah.
هُما صَاحِبَانِ لِي
Those two are my friends
قَرَأتُ القِصَّتَيّنِ
I read the two stories
سَلَمتُ عَلَى الشَيخَيّنِ
I greeted both the scholars
هَاتَانِ السَيَّارَتَانِ جَدِيدَتَانِ
Those two cars are new
