"you may not realize this but before to get full citizenship you were required to know english."
Yes this is true, after my sting in the US Army, and after I waited the 5 years, I send in the paperwork required to become a citizen. The day came were I was to bring my 2 American character witness and for a interview were I was asked, in English, if I could speak the language, asked to write a sentence in English, and asked some questions about American History and political set up of the country. After 5 years in the country and 2 years in the US Army, I did not have any problems passing this test.
"Same when driving I have seen so many imigrants blatantly violate streat signs that give written instructions in english. leading to collisions or near misses"
The problem here is that there is cottage industry that will sell you the answers to the question on the driver's test, people simply memorize the answers, but, they really do not know the law, end result: people ignorant of the law that really do not know how to drive. One way to prevent this is to have different tests from different parts of the law, and provide those test in a random fashion.