Just a disclaimer: I'm not a linguistic, nor a student of linguistics. I do have some comments which might give you some insights and food for thought regardless.

Firstly, there are several complications to your question, the first and foremost being that in pre-modern times, languages which we now classify as singular entities "Norwegian" and "German". Most official national languages are products of standardisation which is strongly related to nationalism in the 19th century. These national languages were by no means always 'natural' historical outcomes, but were often based on a certain dialect which was then consciously spread by politicians with a national agenda. I can't give you an exact percentage from the top of my head, but around the time of the French Revolution, the Parisian dialect which was to become standard French was spoken by only a very small portion of the population. In Germany, whilst Luther's translation of the Bible is arguably the starting point of very long history of standardisation, but it only became a conscious effort around the 19th century with the rise of Prussia, and dialects still widely exist in Germany today.

A second compilation with regards to the classification of languages, is that it is very hard to narrow down objective criteria to what constitutes a langues and what constitutes dialect of that language. Once, I was doing a German language course and an English linguistics student thought Dutch was essentially just a dialect of German. My inner Dutch patriot was initially offended, but I clearly couldn't deny that there are structural similarities between Dutch and German, so where exactly do we draw the line linguistically that these are separate languages? But do these distinctions justify classifying other languages as languages, because with so many different languages there is an almost endless amount of possible differences between languages? Perhaps the term "language" is just tied to a particular era with the particular age of the nation-state, not so much linguistics?

Now for an actual example that might show you something. In English, 'Dutch' refers to the language of the nation-state of the Netherlands. However, historically it largely applied to all the Germanic lands on the other side of the North-Sea, I guess you could say to the English it was essentially all the same gibberish. In middle-Dutch, the native word for Dutch was 'Diets' (sounds very similar right) and also applied to the overlapping blanket of dialects East of the North Sea. But nowadays the word for Dutch in Dutch is "Nederlands" which doesn't sound similar to the term 'Dutch' at all. But it comes from 'de Nederlanden' (literally the low lands) which is historically older than 'Nederlands' and as far as I am aware historically an long existing term to refer to this area. What changed? When did we shift from using 'Diets' (linguistally related to 'Dutch') to Nederlands to refer to our language and by extension us? I can't tell you exactly when the shift happened, but it is a consequence of nationalism, and one that likely finds it origin in the uprising against the Spanish starting in the 16th century. Modern day languages and 19th century nationalism are strongly related. Before the processes of standardisation, languages were much more diverse and essentially a blanket of many different dialects with certain characteristics and features slowly changing the more you'd travel away from a certain starting point.

I hope this makes sense, I saw no one had answered yet so I figured I'd just share my thoughts :)