If you read the Washington Post report on the student who was expelled for answering a question in Spanish, I hope you are asking yourself that question.
I can see encouraging students who are learning English to speak the language, but this kid was bilingual. What harm does it do? We should be praising him for being able to speak two languages. But instead, we expel him.
This is old thinking. Native Americans used to be punished for speaking their languages in school. Mexican Americans were often punished for the same thing. But that was 30 or more years ago. Have we really learned nothing?
Check out the article if you haven't yet.