Removing language barriers to limited english-speaking populations is the main focus of:

That would be linguistic competency. This concept was first introduced by Noam Chomsky and it is not to be confused with the concept of linguistic performance. Linguistic performance deals with how language is actually used in real communication while linguistic competency is the system, the ideal system, which allows the speakers of the language to see the differences between the correct sentences and the bad ones while also allowing them to create and understand an infinite number of different sentences in their language.