1 he familiarised/trained himself with local customs/habits before he travelled to the foreign country
2 we met people from different civilisations/cultures during our travels
3 In Japan it`s common/ordinary to eat rice
4 While living in Japan, we came to estimate/appreciate how important it is to be polite
5 Peter is a native/local speaker of the English language
2) cultures
3) common
4) appreciate
5) native