A weak-final root may end underlyingly in wāw or yāʾ. The distinction is about the root, not merely the last letter visible in one inflection.
دَعَا — يَدْعُو — اُدْعُ: underlying wāw reappears in the imperfect and imperative.
رَمَى — يَرْمِي — اِرْمِ: underlying yāʾ reappears in the imperfect and imperative.
رَضِيَ — يَرْضَى: a visible yāʾ in the perfect does not prove a yāʾ-final root; the underlying root is ر ض و.
Opening interactive controls...
Weak-Final Wāw and Weak-Final Yāʾ
Defective Verbs: Six Iʿlāl Rules and Four Short Paradigms
A weak-final root may end underlyingly in wāw or yāʾ. The distinction is about the root, not merely the last letter visible in one inflection.
دَعَا — يَدْعُو — اُدْعُ: underlying wāw reappears in the imperfect and imperative.
رَمَى — يَرْمِي — اِرْمِ: underlying yāʾ reappears in the imperfect and imperative.
رَضِيَ — يَرْضَى: a visible yāʾ in the perfect does not prove a yāʾ-final root; the underlying root is ر ض و.