There are so many fascinating things about languages. Here are a couple: - Toss people together who don't really have a common language, and they quickly evolve a pidgin, which is a very simplified kind of language that lets them communicate. Over a couple of generations, the pidgin evolves into a full language. This has happened repeatedly over history, often through things like conquering or enslaving other groups…
Just as a little correction: Dutch is not an "evolved German dialect". German and Dutch are both West Germanic languages, but so is Scots, Frisian and English. So it would be like saying that German is an evolved English dialect then (though to be fair, Dutch and German are grouped closer to each-other in that family tree usually and have provided a lot of substrate for each-other due to close contact). Swiss German…
If we go a few hundred years or so it would’ve been considered a language as much as any other German “dialect”. But somebody decided to pick another dialect to be the “standard German” language.
Same applies to France and Italy. Especially when some northern Italian “dialect” are actually more closely related to “French” and some southern “French” ones to Catalan.
Just like for instance Dutch interestingly enough is closer to Franconian than to Frisian.