Is this sentence grammatically correct?
It did not come out of nowhere, Michael.
As I know, we can't use two negatives in the same sentence. Can I use this sentence at IELTS Writing Task 2, where I'm not as restricted as at Writing Task 1?
Thank you in advance.
I don't think "out of nowhere" is a negative-polarity expression*. I think it is an idiom, which has had its negative polarity "bleached" out.
So its meaning "unexpected, surprising, intrusive" is constant whether the verb is negative or not:
Well, that came out of nowhere, didn't it!
It didn't come out of nowhere: there's been discussion on social media for days.
Out of somewhere and out of anywhere are perfectly grammatical, but do not partake of this meaning.
*It is possible to use it literally, rather than in the idiom, but I don't think it is common: You've copied that essay out a book, haven't you? No, I copied it out of nowhere!. In that use it would have negative polarity, so in standard English No, I didn't copy it out of anywhere!, but in non-standard versions No, I didn't copy it out of nowhere! (Compare standard I didn't touch anything! and non-standard so-called "double negation" I didn't touch nothing!)
It did not come {out of nowhere} = it came {from somewhere}
The phrase is grammatical and it means "Something caused it".
When we say "That remark seemed to come out of nowhere" we mean that it was a non-sequitur; it did not seem to flow in any way from the conversation going on at the time.
Or if we say "And then this truck came out of nowhere and broadsided me" we mean that it was not seen coming. It just suddenly appeared.
So, to say that something "Did not come out of nowhere" the meaning would be that the speaker believes there's a reason behind it or that it is not the non-sequitur or unexplained phenomenon that it may seem to be or that it is presented as being.
