"I ain't got no time." Bugaboo of English teachers every where. If you believe in mathematical logic, then you understand that negating a negative makes it positive. A hard concept from 8th grade math class. If A is a proposition then not A is the opposite. If A is true, not A is false. And not not A is true.
And yet the double negative persists in speech. That's because it seems natural that two negatives make the negation stronger.
"I ain't got time" doesn't sound as emphatic as "I ain't got no time".
But the English teachers of the world are united in condemning the double negative and their view is likely to stick.