So is this pronounced “mon-ta-goo/gyou” or “mon-taig”? (sorry for my lousy phonetic breakdowns)
I’ve always heard “Montague” as “mont-ah-gyou.” I went to look up the etymology (I think it’s from Old French Mont+acute) but there’s no good evidence, a sort of “Wherefore art thou Montague?” situation, if you will. 
It may be in use somewhere, but I’ve never heard “mon-taig”.
Thanks. All I had heard was the Mont-ah-gyous and Capulets, but we have a Montague street and I heard someone pronounce it Mon-taig. Just wanted to make sure there weren’t some Montaigs out there.