There are a few potential problems which limit the significance of this:

1. There is not a universal definition of what defines a language and what is simply a dialect or a regional variation; this applies especially on large continents where there can be greater variation in language features between geographically remote locations, but no clean boundary at which you can say people speak one or the other language.

2. Languages evolve, diverge and sometimes borrow, and so a group of related languages can share the same potentially idiosyncratic feature because of common evolutionary roots rather than because the feature makes sense. This could explain the result for Hindi - it is a standard language that 'averages' a large number of other Indian languages.