Danish / Norwegian
Norway was occupied by Denmark for 400 years and so their languages are nearly the same (see note at bottom of page).
Norwegian - Old Norsk Version
When their Majesties the King and Queen of Norway were going to be present for a ceremony dedicating a peace pole to them, the languages were carefully vetted. A photograph of a peace pole in Norway was gotten for me so that I could see the translation that Norwegians use for their own language. It turned out to be the translation that I was using for Danish.
I explained that to a Minnesota Supreme Court judge who had been ordering plaques from me, was ordering more and had proved to be a careful researcher. He said that the Norwegian Royal Family's roots go back to the Danish Royal Family that sat on Norway's throne, and so they may tilt toward the Danish. He ran it by people in Norway who said that both are correct now. The judge said he preferred the Old Norsk version that I originally had been using for Norwegian.
They can be used interchangeably, but if they both are on the same peace pole, their differences distinguish them.
In both languages, Fred is the word for Peace.
During the centuries that Denmark occupied Norway, Danish was the official language for every formal occasion and process. Eventually the Norwegian language was being used only in rural areas and was dying. But a man began a campaign to travel to those rural areas and collect the Norwegian words that still were being used. He published them as New Norwegian. It really only was rediscovering Old Norwegian, but it re-established traces of the language.