Check to make sure the Hindi collation is setup on the server on which you are doing the query.

Other than that, I don't know what answer to give you. Soundex() is not my favorite function. It's hardly perfect, and I'm not sure what libraries it uses to pull its code translations from. It could be that it's not set up to deal with non-English languages very well. It could be you're missing a library. I'm not sure.