To the best of my knowledge, the United States does not have an official language. This adds extra pressures on first responders (police, fire fighters, EMS crews, etc) to be able to get to a location in a timely fashion. Also, the extra paperwork that hospitals, DMV offices, traffic & business signs and paperwork that must be kept on hand is insane. Hospitals should not be forced to keep multi-lingual copies of the same document. Driving exams should be made in English (if you cannot read the test, you should be able to drive, and yes this affects illerate people as well).
If you are proud of your ethnicity, that is fine, this country was found on immigrants. If you want to have your own street signs, I have no problems with this, but at least make it so others can read them.