There’s a grammatical rule in English that says, put in William Safire’s Fumblerules style, “Don’t use no double negatives.” Let’s look at that for a bit....
For one thing, the way we treat negatives is specifically English. Consider these:
English: ...more than ever.
Spanish: ...más que nunca.
Translation: ...more than never.
English: Don’t tell me anything.
Spanish: No me digas nada.
Translation: Don’t tell me nothing.
English: Neither red nor green.
Spanish: Ni rojo, ni verde.
Translation: Nor red, nor green
Of course, I’m not suggesting, here, that English should follow the idioms of another language. It’s just an interesting comparison, and it points out why non-native speakers often have trouble with this in English.
But also note that the second, “Don’t tell me nothing,” actually is accepted idiom in some English dialects. While being formally incorrect, it’s certainly in common usage.
Of course, that usage confuses no one; only a child, or someone emulating one, would respond to, “You don’t know nothin’!”, with, “That’s a double negative, so if I don’t know nothing, that means I do know something!”
A usage of negatives that bothers me is one I hear often; often from intelligent, educated people; sometimes, even, on NPR (where I heard one the other day): “I miss not [doing X].”
“I miss not going to the beach.”
“I miss not seeing my brother.”
“I miss not being married.”
The “I miss” gives us the first negative (implying absence), and for the first two we can surely understand that the speaker means to say that she misses going to the beach and that she misses seeing her brother — the “not” is a superfluous second negative. But, well, what about the third example?
Spoken by a recent divorcée, the third would express sadness over the divorce, using the same double negative. But a bored wife might say the same thing, intending to be taken at her word: she pines for the single life.
Another related error with negatives is using “all [X] are not [Y],” when you mean “not all [X] are [Y].” Years ago, someone in the technical publications department sent a note around, listing the publication numbers for manuals for a new product that was soon coming out. One of the recipients tried to order a couple of them, and the order failed because the pub numbers were “invalid”. He questioned this, and the guy who’d sent the list said, “Yes, all those manuals aren’t available yet.” Then why, one of us asked, did you give us the list now if we can’t order any of them? “Well,” he said, “because you can order some of them now, of course.” He didn’t add, “you idiot,” but it came across anyway.
And, of course, the point is that it wasn’t the one questioning him who was the idiot. What the pubs guy had meant to say, though he didn’t know it, was, “Not all of them are available yet.” Or, alternatively, “Some of them aren’t available yet.”
And that’s why confusion with negatives can be... confusing. You know what you mean when you mangle them. But don’t be surprised when others aren’t sure, or misinterpret you outright.
There’s a reason we use standard language when we want to communicate.
Not to call out song lyrics as exemplars of anything, of course, but another familiar double negative comes from a 42-year-old song by the Rolling Stones:
I can’t get no satisfaction.