I'm a great fan of using Norwegian words whereever applicable instead of importing English (or other foreign) versions of the world.
Skjermbrev
Wonderful Norwegian word for "screen letter", i.e. email.
Skjerm
Why on earth do people use "monitor", when there's perfectly good words in their own languages?
English words and expression often causing problems for Norwegians (and maybe others too)
Priest
"Priests" only exist in the Catholic church. If you're talking about a Protestant church leader, 'minister' is the word you're looking for.
First floor
Remember, in English, the first level is called "ground floor" and the second is called "first floor".
Mile
In Norwgian, a mile is ten kilotmetres. In English, however, it's one and a half kilometre!
God day
Although it's possible to translate "God dag" with "God day", it may be considered rude (or even awkward) to say so as a greeting. Just say "hello" instead.
Congratulations (birthday)
In English, you only say "congratulations" when the person has accomplished. Although it can be hard to be alive sometimes, it's hardly considered an accomplishment to have managed another year. Thus, don't say "congratulations", use "happy birthday" instead.