مُكَبَّرَةً means the noun must be in its regular, non-diminutive form.
أَخُوكَ: the ordinary “your brother” form; the condition is met.
أُخَيُّكَ: a diminutive, “your little brother,” which uses ordinary vowel endings.
جَاءَ أُخَيُّكَ، رَأَيْتُ أُخَيَّكَ، مَرَرْتُ بِأُخَيِّكَ.
Translation: Your little brother came; I saw your little brother; I passed by your little brother.
The special wāw/alif/yāʾ pattern no longer applies to this diminutive.
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Noun Case Classes: Type 4 — The Six Nouns
مُكَبَّرَةً means the noun must be in its regular, non-diminutive form.
أَخُوكَ: the ordinary “your brother” form; the condition is met.
أُخَيُّكَ: a diminutive, “your little brother,” which uses ordinary vowel endings.
جَاءَ أُخَيُّكَ، رَأَيْتُ أُخَيَّكَ، مَرَرْتُ بِأُخَيِّكَ.
Translation: Your little brother came; I saw your little brother; I passed by your little brother.
The special wāw/alif/yāʾ pattern no longer applies to this diminutive.