Yes I some way that's true but not 100%, people from southern site of india do not feel comfortable with hindi we should respect them, actually indian constitution says that the government of india should promote hindi and make effect to limiting English, I am living in uttarakhand and since independence we are following Hindi but I never faced that our local dialect is being backward because of hindi.
So it's good to have india speaking a single language it can be any language. official language of india there are two official languages hindi and English but we don't have any national language,