An accent that is hard to understand
Even though the main language that is spoken is English, don't be too discouraged if, when you arrive, you don't understand a word that the local say - it's only to be expected! In fact their accent, combined with the speed with which they talk, makes them extremely difficult or even impossible to understand. You'll take a while to adapt and quite honestly, even after living there for a year I still couldn't understand some people! New Zealanders of Maori heritage also have an accent all of their own, which can also be hard to come to terms with. Why not familiarize yourself in advance by watching the movie "Boy" (without subtitles) by the Maori director, Taika Waititi?
Maori is a language that is still spoken in the country, but generally by the tribes among themselves. If you're feeling brave, you can try to pick up a few words!
For those who want to learn some basic English, here are some words to know and some useful phrases for your stay in the country of New Zealand.