Globalize, or face extinction
A woman who recently moved into the Tacony section of Philadelphia received an anonymous letter in the mail that began: "if any of you understand English, which is spoken here in this country, then all of you in this house better pay close attention," then went on to call the woman and her family "sub-human species" and threatened "to firebomb your house."
To the writer of this letter (and anyone who may sympathize with them), I say the following:
First, your letter is anonymous. That tells me you're too scared to reveal who you are to the public.
Second, you make threats. A person who makes threats is someone who feels threatened. So again, that tells me you're scared.
Third, while a small, but sizable and vocal, minority of cultural conservatives in this country angrily insists on nationalist and xenophobic policies, the rest of the world is globalizing, and fast. While some Americans (like the writer of the letter above) are pouting about English-only, people all over the world are learning second and third languages!
Now, putting those three points together, I'd ask that the anonymous writer come forward to the public to apologize and ask for forgiveness. You clearly need a hug and reassurance that you have no reason to be scared. Yes, the world is a big place with a lot of people who look different and talk differently than some of us here. Yes, change is difficult, but with some effort and openness to meeting other people, you'll be okay.
On the larger scale, quite to the contrary of English-only, we must be encouraging everyone who lives in the U.S. to learn at least a second language! Look at the world around you. Unless the U.S. is going to get left in the dust, we must keep pace (or better yet, get ahead of the pace) with the world around us. In the field of communication (which at its essence is the basis of all human interaction), that means adapting to a globalizing, multilingual world.
So please, to the anonymous writer above and all sympathizers: download the duolingo app to your phone (or something similar) and convert the energy of your fears to something productive and helpful: learning a new language. Oh, and love thy neighbor.