So isolated they didn't use Yiddish as their primary language?

I said they didn’t bother to learn the language of the locals in Poland. That would be Polish, not Yiddish.

And yes, they did interbreed, because most Jewish scripture was written in the fucking Bronze Age, and they thought one of the sexes (can't remember which one, think it was females) couldn't pass along their "blood".

I can only speak on their history in Poland, which as you should know, is substantial. There it would have been quite rare if it happened at all, as they were isolated and both communities distrusted the other.