Earlier quoted context omitted.
No, it doesn't help, sorry. A language can't be deterred. Only animated objects, such as animals and people, can. Your sentence doesn't make sense.
Actually, deter has two uses. From MW: Definition of deter transitive verb 1 : to turn aside, discourage, or prevent from acting she would not be deterred by threats 2 : inhibit painting to deter rust I have also seen "crime" and "war" given in examples of sense 2. To "deter the language", in sense 2, would be to deter speakers from using the language. You can sort of unify the two senses by treating "rust" or "war"…
Well, I know the general idea that he's trying to convey, since it's the same sort of message that I read in the nationalist press (e.g. El Mundo) day in day out, but I think if you intend to have a productive discussion you have to talk precisely, otherwise it's a waste of time. To say that a language is being "deterred" is not precise, it's vague and confusing, even if not technically incorrect (although I doubt that).