Compare تَقَبَّلَ with تُقُبِّلَ.
The visible change is:
1. The prefixed Taa and the first root letter carry Dhammah.
2. The doubled middle root letter carries Kasrah.
3. The result is تُقُبِّلَ.
Opening interactive controls...
How the Passive Past Changes
Derived Trilateral (without Hamzah) - Bab 3: Tafa''ul (Taqabbul)
Compare تَقَبَّلَ with تُقُبِّلَ.
The visible change is:
1. The prefixed Taa and the first root letter carry Dhammah.
2. The doubled middle root letter carries Kasrah.
3. The result is تُقُبِّلَ.