Correct me if I’m wrong...
Don’t LEGAL immigrants that become naturalized have to be able to speak and read the American English language?
How can it be that people who can not do so are allowed to vote?
There are exceptions to the rule. For instance, the 20/50 rule. If you have been here 20 years or more and are over 50 years old, the “read and write English” provision is waived for naturalization.
At least that was the case when I worked for INS 10 years ago.