Hello. 
I don’t think there is a readily available technique to do as you’ve asked.
However, I participate in several communities where we encourage non-English usage, and still only get regular ol’ English instead. 
So let me ask you: what challenge are you having? And also, how do you define “English”? Are you referring to the character set (UTF-8)? Or… common word usage? Like, are you more concerned about someone talking about sushi in your forums, or more concerned about someone talking about すし?
I love talking about language! すごい!