Дать ответы - Kiswahili

Проголосуй сейчас!НеотвеченныйЯзыковой вопрос
Tofauti kati "wangu" na "yangu"

Why do you say "rafiki yangu" but "mjomba wangu"? It both means "my", it's both about a male person, it's both singular. Can anyone explain that to me?