American English has three languages that we do most of our cultural trade with.
Commonwealth English
Mexican Spanish
Franciscan French
In both of the latter, multiple casual negative modifiers are additive instead of inverting. That is, they have the semantics of "bad" instead of "not.".
And surprisingly, people speaking such languages as well as English can learn that each language works differently and use the correct form. (Speaking from personal experience.)
It's a double-negative. Classic grammatical mistake that is sadly quite common in some modern parlance. Blame culture or the education system, but don't make the mistake of thinking the person saying this is actually trying to slyly indicate they did do something while seeming like they're denying it. That's not what's going on.
Remember: don't use no double-negatives and don't never use no triple-negatives!
That's naïve. One can appreciate differences in grammar usage and take them into account when trying to understand someone else in the context of cultural differences and still acknowledge that grammar has formal rules. If you're just going to say that grammatical rules can be ignored, why bother teaching grammar at all? Because as much as there might be deviations from the norm, there is still a norm, and it's important there is one. One cannot appreciate jazz without learning classical musical structures; the existence of jazz does not negate that music has said structures, and jazz wouldn't be jazz without them.
in some Austrian/Bavarian dialects people say things like "i hob koa Gööd ned" which translated word-for-word to Standard German is "ich habe kein Geld nicht".