I am researching the sociology of language and socio-linguistics, and my area of specialty is bilingualism. In other words, people who live in a community and speak that particular language, but then have to live in another community, too, and therefore they have to speak both languages because their network of interactions requires it.
Nations define themselves as having achieved cohesion through monolingualism.
So, although the academic acquisition of a second language is considered an asset, bi-cultural bilingualism is potentially very problematic. This, of course, is not a new concept. In Mexico, Malinche, who was the translator for Cortez, was not entirely trusted by the Spanish, and she was viewed as a traitor by Mexicans. The multiplicity of languages is seen as one of the problems with a nation such as India and one of the reasons why they haven't been able to achieve a modern status. But the truth is, we don't really know that this is always going to be the case.