Zaydun akhūka: nominative antecedent and nominative badal with wāw.
Zaydan akhāka: accusative antecedent and badal with alif.
bi-Zaydin akhīka: genitive antecedent and badal with yāʾ.
Badal follows grammatical case, not necessarily the same visible ending. The latter two are teaching examples.
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Badal: Definition, Four Types, and Parsing
Zaydun akhūka: nominative antecedent and nominative badal with wāw.
Zaydan akhāka: accusative antecedent and badal with alif.
bi-Zaydin akhīka: genitive antecedent and badal with yāʾ.
Badal follows grammatical case, not necessarily the same visible ending. The latter two are teaching examples.