It’s an article of faith for English majors: Two negatives make a positive. So, in the minds of these jurors, “didn’t do nothing” = “did something.”
If they had majored in linguistics, they wouldn’t make that mistake. (Sorry, English majors!) Many languages have double negatives; they’re a form of emphasis. Spanish and Welsh are examples, and – surprisingly – so is English. Old English and Middle English, that is. Yep, our Anglo-Saxon forefathers (and foremothers) routinely used double negatives.
Here’s an example: In the “Friar’s Tale” in the Canterbury Tales, Chaucer used a double negative: “Ther nas no man no wher so vertuous.”
English isn’t mathematical, and it isn’t logical. Languages evolve in their own way, often defying common sense…and English majors’ attempts to inject sense and structure.
Everyone who’s ever studied formal grammar knows that you can’t say “It’s me” because the copulative verb is requires a nominative case pronoun (I, in this case).
But wait a minute! French speakers say “It’s me” (“C’est moi“) all the time.
So that means I advocate throwing out all the rules, right?
Language rules arise from the desire to fit in with the group of speakers you belong to (or the group you aspire to belong to). If you want to hang out with educated professionals, your speech and writing habits need to match theirs.
In the 21st century, educated professionals generally don’t use double negatives.
It’s that simple. It’s even logical. (But not mathematical.)
(To learn more about pronouns, click here.)