‘An A-Z of English Grammar and Usage’ by Leech and others suggests the following:
With be, use the contraction + not (e.g. That’s not
right).
With have and modal auxiliaries, use the verb + n’t
option, e.g. hasn’t, can’t.
The authors go on to say that forms such as She isn’t hungry, as opposed to She’s not hungry, are less common, and that forms such as I’ve not met him, as opposed to I haven’t met him, are much less common.
The authors don’t say on what basis they make their recommendations, but they are likely to be based on frequency of use. There doesn’t seem to be any difference of meaning or emphasis. I would just add myself that a contraction such as I’ve not met him sounds more formal, perhaps because of its lower frequency.
This expression X has nothing to do with Y can mean two things (at least):
- If Y is the word "you," it can mean X does not concern you. When used in this way, the expression can be used in a somewhat unmannerly way, as if to say, "X is none of your business!"
Ted: I think maybe you're spending too much money this Christmas.
Ed: What I put in my shopping cart has nothing to do with you.
- It can also mean X is not the cause of Y. In the following dialogue, assume Ned is a salesman who had no sales last month:
Ned: Our team won Team of the Month. We should go celebrate!
Ed: Ned, you had nothing to do with this award.
(That could be regarded as a harsh remark, but the phrase can also be used in a reassuring way, to say that something is not your fault:)
Jed: What a calamity! I feel so bad that this happened.
Ed: Don't fret about it, Jed. You had nothing to do with this.
Back to what you were trying to say:
4am has nothing to do with your English.
I guess I can sort of see how this might mean the time of day doesn't affect your English, but I'd probably not word it that way. Instead, I'd say something more along the lines of:
Your English is great, even at 4am.
As for the other way around:
Your English has nothing to do with 4am.
That one seems a bit harder to catch the meaning. I might word that like this:
Your English isn't affected by the time of day.
Your English is good round the clock.
Best Answer
People say that.
We might get taught in schools not to say it. But to some people it's the natural way to talk. It's not ungrammatical to them.
It would probably be ungrammatical on a test of so-called standard English. But who decides what is standard? The test makers and those with socioeconomic power.