lol that depends. If they are mostly from South India, learning Hindi might not move the needle as much. Might want to pick up some Kannada, Telugu and/or Tamil. Would be pretty cool for trying, and it’ll probably make your outlook favorable

In the bay area, I've met relatively few NRIs who don't know Hindi well, even if it's not their first language. Most of them that I've met are not even Kannadiga, Mallu, Telugu, or especially not Tamil. Sample size of at least several dozen.

The irony is ethnic Indians in the U.S barely speak any of those.