Even if they’re here legally, if they can’t speak English they shouldn’t be driving.
Disagree. First, most states have driver's tests in multiple languages. Second, it is not necessary to speak English as long as you can recognize most of the common road signs. There is a reason why the signs are different shapes. Finally, we accept international driver's licenses from the more than 50 million visitors who enter annually and/or we have reciprocity agreements with various countries on accepting their non-commercial driver's licenses, e.g., France and Germany.
I have lived overseas 25 years of my adult life in nine different countries. I drove in every one of these countries along with many more without speaking the language of those countries.