French Wikipedia seems to have an article about it https://fr.wikipedia.org/wiki/Mayennais https://fr.wikipedia.org/wiki/Mayennais including some purported vo

French Wikipedia seems to have an article about it https://fr.wikipedia.org/wiki/Mayennais https://fr.wikipedia.org/wiki/Mayennais including some purported vocabulary, plus a few books that discuss it! Some of them discuss it as "bas-mainiot" or "patois du Bas-Maine", of which Wikipedia says "Il [Département de la Mayenne] correspond essentiellement au Bas-Maine, qui formait la moitié occidentale de la province du Maine"... I guess you're probably very familiar with these geographical designations, but I'm definitely not! Google has a scan of a 1975 reprint of an 1899 book about "les parlers du Bas-Maine" which includes tons of references to speakers and lexical items observed in Mayenne. https://books.google.fr/books?id=mcykCmekgioC https://books.google.fr/books?id=mcykCmekgioC (It's sad that some pages are missing from the preview... maybe Google algorithmically concluded that the book might still be in copyright because it was "published" in 1975.) But it's true that a Wikipedia article isn't the same thing as finding a thriving language community online.