I am a natural born citizen of 63 years of Native American descent. I believe if you want to live in and work in the United States, you need to learn English and use it if you are working in a place like Wal Mart or any other US company.
People come to the US for the opportunities. Along with the opportunities come responsibilities, and one of those responsibilities should be to learn english and speak it so that you can effectively communicate with people.
I believe learning english should be a requirement of citizenship.