* "Ndugu" is the most general term for brother, which can also mean sibling, relative, or even friend.
* "Mdogo" means "younger brother," but can also mean "younger sibling" in general.
* "Mkubwa" means "older brother," but can also mean "older sibling" in general.
* "Dada" means "sister."
To be specific, you could say:
* "Ndugu yangu" (My brother)
* "Mdogo wangu" (My younger brother)
* "Mkubwa wangu" (My older brother)
The choice of which word to use depends on the specific context and the relationship between the speaker and the listener.