Yes - you guys need English as a link language to communicate as quite a few of Indians dont know and some refuse to learn English.
India has implemented this. Each state has its own language as official with English and Hindi used as business languages. In Maharashtra everything is in Marathi, Road signs, signboards, Court Language, Mandatory subject in schools etc. In Gujarat it is Gujarati, Karnataka - Kannada. It is bit of confusion because Indian language scripts are different. So a Maharashtrian going to Kerala would not be able to read Malayalam signs.