Can i trust the Romance language family trees?
You can trust them as much as you can trust most linguistic family trees — in fact, since we know so much about the history, you can trust them more. However, they are only as reliable as biologists’ phylogenetic trees of species. All such representations present a simplification of reality. Most importantly, in the case of languages, they obscure a great deal of borrowing — mainly lexical, but also phonological and syntactic. They also tend to imply a greater degree of separation between languages than exists. Famously, there are some dialects of Dutch that are more like some dialects of German than they are like some other dialects of Dutch. It is similar in the case of the Romance languages: we are often dealing more with continua than neat categories. That said, linguistic family trees are useful inasmuch as they give a reasonable overall picture of where the big splits were and what languages have a longer shared history. This is based on a combination of lexical, syntactic and ph
