This comment is simply false. We can have a robust sharing of ideas and cultures all within the context of a single language.

In speaking a common language we gain tremendously both in unity and the opportunity for increased cultural sharing. Imagine a family in which everyone speaks different languages. There would be little interaction; the family would fall apart. Nations have historically fractured in this way along linguistic boundaries, and by not encouraging a single language in a country, we invite division, balkanization and national fracturing.

I'm curious as to why you are against a single language dominating in a country. Are you uncomfortable with people being expected to make the effort to learn a new language? Or do you just not care about nations (or the USA in particular) as units and don't mind if they fall apart.