When 2 Negatives Don’t Make a Positive

Those of us who learned about double negatives in grammar class understood them as grammatical no-nos. You were not to say, “I don’t have no bananas,” because, by denying the absence of bananas, you were confirming their presence rather than (as you presumably intended) confirming their absence.

The issue of double negation has arisen in recent decades because African American Vernacular English uses double negatives frequently. Other languages, as many have observed, regularly employ what would...