Is it necessary to ask her father for permission?
Yes, you must bring him 12 carp fish and lay them at his feet, the elders of the village will then expect 2 metres of smoked sausage each as they listen to your plea for the hand of one of their own. You will then need to have her first names written on your forehead in henna, before kneeling before the grandfather who will pronounce their decision, which will only be favorable if the tribes people remove their head garments and sacrifice a cockerel.
Other than that, it's exactly the same as in Britain, except you need to bear in mind they may prefer you to be religious if they are.
