Language Barriers

First off just wanna say I like this show a lot. I think it's clever and charming in a way, and very funny. However there's one thing that has really bothered me since the first episode, and now starting season 2, I'm seeing it more and more.

At first it was Frankie boy knowing everything the Norwegians were saying perfectly, even though he can't seem to mutter a word of Norwegian back to them. Yet the 2 sides magically understand each other. And it isn't just Frank, it's every foreigner in the show. When the 2 New Yorker's come after Frank towards the end of Season 1, they do the same thing. They speak to Norwegians in English, and vice versa. We're supposed to believe these 2 random New Yorkers will suddenly understand everything? At the beginning of season 2, the Scotland Yard investigator speaks to the police in English yet understands fluent Norwegian when the police speak back to him.

I know that this is done for the actors' benefits so they don't have to learn Norwegian to act, but it takes me out of the show a little. Can't they hire actors that just speak English and have everyone speak English? Or in situations where the person can't possibly know Norwegian, can't they include a translator or something? It's very distracting the way they do it.

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 Idiots