What Syllable Would You Not Be Allowed to Use?

If you count Eurasia as an island, five down to three. It doesn't include Australia. After I think it's after Greenland. The country is called Papua New Guinea. A woman can't use some married women following the system of balisha. They are not allowed to use words that begin with the same syllable as your father-in-law's name or your mother-in-Law's name.