This is what happens when you try to translate a phrase directly from one language to another.
the person you call John Njeru Kimathi, is actually John Njeru wa-Kimathi....or John Njeru mtu-Kimathi (John Njeru M'Kimathi)....or John Njeru ole-Kimathi..... John Njeru arap-Kimathi
The "wa", "mtu", "ole", "arap" etc signify that he belongs to Kimathi.
His wife is Kwamboka wa-Njeru and all his children are xxx wa Njeru.
Now there is no confusion.
But what should happen if John gets his PhD..... and gets promoted to the post of Professor?
Nothing is real unless it can be named; nothing has value unless it can be sold; money is worthless unless you spend it.