وَهُوَ أَيْضًا خَمْسَةُ أَلْفَاظٍ لِسِتَّةِ مَعَانٍ.
Translation: Addressee marking likewise uses five expression types to cover six person/gender/number meanings.
كَ (one male), كِ (one female), كُمَا (two of either gender), كُمْ (male/mixed plural), كُنَّ (female plural). The listener and the indicated referent are different dimensions.