Is it possible to control the development of language externally?

An example being aliens living in hidden spaceships outside of our atmosphere but doing things during our history to control how our language developed.

How would they do this without revealing themselves?

Edit:

The goal of the aliens is to allow two species from different planets who have not yet met to **talk** with relative ease. This means they can either manipulate current languages or maybe create a new language and convince everyone to learn it. The language should be known by the higher educated people on both planets, but not necessarily everyone.

This is for a story, not a conspiracy theory :P