Norwegian is not on this list, because in fact no country with Norwegian as their national language is part of the European Union at the time of writing.
"Norwegian" isn't just one unified language and Norway isn't in the EU.
That being said, the Scandinavian languages all come from old Norse, and modern national constructs aside, most of the people in the those areas descend from the same mix of Germanic tribes. There's no denying that modern-day Danish, Norwegian and Swedish are very similar.
I have often joked that Norwegian is just a dialect of Swedish, but I never expected to get official validation like this!