Actually I was saying the total opposite of what you inferred. I thought that despite being in Mumbai, IIT-B would have a very diverse spread of folks due to the methods of intake(JEE/ all India recruitment of professors). That means Marathis might not be the language of choice, because it's highly likely that the researcher is Tamil/Telugu. Unlike someplace like, say, VJTI, that's likely to have a large Marathi population.

(I didn't downvote btw.)