How to be with locals especially some of them can't understand you?

Hi where do you live?

Understanding is a subjective term and does not depend on language alone.
I never lived in India, but visited for extensive periods and found that English is widespread enough (at least among the educated classes) to make myself understood in most situations. Befriending someone of course requires a different level of understanding - and in this respect it is you who must take the lead, e.g. by learning their language, adopting their habits or at least showing respect and interest.
Hinduism is a very diverse and also inclusive religion. I am sure you'll find your niche in it, if you want - just as Jesus did (he was a wandering monk in India for a while, or so the Hindus claim).

As of now I'm here in Mumbai