Many English learners, and even a lot of native speakers, often make the big mistake of using a double negative in speech. Even though some native speakers make this mistake, it shows poor use of the language and can sound quite ugly.
So, what is a DOUBLE NEGATIVE?
Double negatives are when you use 2 negative words in the same clause (part of the phrase) in reference to just 1 negative idea. The most common example would be, “I DIDN’T do NOTHING.”
Using the auxiliary verb (didn’t) in the negative followed by the word nothing, makes this phrase a double negative. The proper way to say this would be, “I DIDN’T do ANYTHING.”