First choice is Urdu: but although Urdu is the official language of Pakistan, it is a bit of a struggle to learn it, and it is not practical. So the second choice is English, and as for British or American, British is better because Pakistan was a British colony. But it seems that speaking Chinese is not much of a problem either, as Pakistan and China are on good terms. So I would suggest that you would be better off learning British English and proper everyday Urdu would be better nevertheless!
Customs and taboos:
People there are rumored to be very hospitable, meet to be very respectful, to become again after adding "will", "Wang Qi".
Pakistanis meet after the implementation of the hand salute is also relatively special, which is implemented between the male Muslims rituals, the method is the two sides of one leg into the shape of a bow, hands clasped, the right hand of the thumbs should be crossed in the inside, the left hand should be auxiliary grip on the outside, the two men's right shoulders close together, while the mouth chanting the scriptures or mutual blessings.
97% of Pakistani people believe in Islam, to do "six faith, five homework". Religious awareness is very strong, and it is evident everywhere. To enter the mosque, the requirements of clean clothes, forbidden to wear shorts, short skirts, not allowed to smoke, and more forbidden to make a lot of noise, singing and dancing, but also prohibited to say obscenities, in order to solemn and cautious as well.
In Pakistan, it is strictly prohibited for men and women to kiss or perform embracing rituals in public **** places, violators will be fined or jailed for a week. Women are not allowed to take pictures of outsiders in public places and are not allowed to look around. Pashtun women are not allowed to go out at will, in the public **** places are not allowed to take off the "hood", but also taboo with their husbands, and even more so with outsiders talk, but also not allowed to watch movies, television.
When visiting temples in Pakistan to take off their shoes, not allowed to smoke and talk loudly. Don't like the color black. It is taboo to give handkerchiefs. It is forbidden to eat pork, meat and blood of dead animals or carnivorous animals. Whoever has had a child die in their family, their women are considered unlucky and cannot be seen. No outsiders are allowed to come to the house for seven days after a child is born in the family. No one is allowed to pat a guest on the back at any time.
This is all the information available at the moment, so I hope it helps!