If:
Then:
Example:
| نَهُيَ | → | نَهُوَ |
When a wāw or yāʾ falls in the ʿayn position of an active participle whose verb is muʿtal, it converts to hamzah.
When a wāw stands as the lām kalimah after a kasrah, it converts to a yāʾ, yielding forms like duʿiya and dāʿiyah.
Morphological rule: a sākin wāw after a kasrah, a sākin yāʾ after a ḍammah, or an alif after a ḍammah or kasrah shifts to match the preceding vowel.
When a و or ي follows a ḍammah in the lām of an ism, the ḍammah shifts to a kasrah and the weak letter is dropped after the two sākins meet.
