In «طَيْرًا أَبَابِيلَ», tanwīn is followed by hamzah, one of the throat letters. In connection, iẓhār ḥalqī retains a distinct tanwīn nūn sound.
This is not assimilation or iqlāb: their required following letters are absent. If you stop on «طَيْرًا», its fatḥah-tanwīn is replaced by madd ʿiwaḍ. Read both conditions and identify the exact reason the sound changes.
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Ṭayran abābīl: tanwīn before hamzah
Al-Fīl and Quraysh: Applied Iẓhār, Ikhfāʾ, Idghām, Madd and Waqf
In «طَيْرًا أَبَابِيلَ», tanwīn is followed by hamzah, one of the throat letters. In connection, iẓhār ḥalqī retains a distinct tanwīn nūn sound.
This is not assimilation or iqlāb: their required following letters are absent. If you stop on «طَيْرًا», its fatḥah-tanwīn is replaced by madd ʿiwaḍ. Read both conditions and identify the exact reason the sound changes.