This should be pretty common knowledge to any linguist who studied historical linguistics, although if you never did any historical linguistics you could easy m

This should be pretty common knowledge to any linguist who studied historical linguistics, although if you never did any historical linguistics you could easy miss that. This should also be common knowledge to anyone who studied late-medieval Latin texts, as many of them use this feature to distinguish the 3 major Romance vernaculars of Europe, e.g. Dante's De Vulgari Eloquentia. There is even an entire region called Languedoc in France, which refers to the language its inhabitants speak (or used to speak). Having say that, although I perfectly know about the distinction between languages of si, oil and oc, I was still intrigued enough to click on the article and it was a nice read (except for the tiny font) and I even learned something new: I didn't know that 'oc' was a calque from Gaulish 'to'. The common case of people sending me articles about linguistics is worse: I often get heavily distorted pop-sci articles full of mistakes and misconceptions.