ENGLISH only in schools will educate and send the message that "you are in America, where the English language is the official/native tongue". Yes, we must implement same treatment throughout our nation to bring back a reality check. The greatness of our nation is preserved in presenting the nation for what it is: an American society, a culture proud of its heritage, a people willing to receive other nations, but not be deluted in the process. I don't want to see other cultures take over who we are.
By the time they're in third grade, these kids typically speak English as well as you or I. They are thoroughly bi-lingual, able to converse without accent, and including idioms, in either language.
My point isn't about what the kids should be taught in school, though. It is that a school principal has no business telling a teacher or anyone else what language they might use. That's just silly, silly, and past ridiculous.