I've been wondering about the difference between questions that use can't you and can you not. Like:

  • Can't you tell just by looking? [I read this from a comic-detective series]
  • Can you not hear me? [I heard this from an animation movie]

So, does it make a difference when you use can't you and can you not? Or anything else like it, such as is it not and isn't it?

I also find that question tags often use those two types of tags, which in my mind are somewhat not interchangeable, such as:

  • It's surprisingly hard to find, is it not?
  • It's surprisingly hard to find, isn't it?

I think both forms are grammatically correct, but I can't figure how they differ each other.

  • 1
    "Can't you interrupt me?" does not mean "Can you not interrupt me?" – F.E. Dec 25 '13 at 18:58
  • The second half of your question is a duplicate of this one. I also feel like we have an entire dedicated tag for this somewhere, though I myself struggle to think of its name right now. Perhaps someone else is more lucky in finding it. – RegDwigнt Dec 25 '13 at 19:47
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    In addition to other answers: “Can you not?” Is also often used colloquially as a rhetorical question by itself (with no main verb) as a shortened way of saying, “Could you please not do that, thank you!”. This is obviously not possible with “Can't you?”, which on its own works only as a tag question: “I can't get the door open!” — “Can't you?”. – Janus Bahs Jacquet Dec 25 '13 at 23:48
  • @F.E. Ah, good point. I voted up your answer. – Safira Dec 26 '13 at 3:50
  • @RegDwigнt: I'm waiting for the answer to that, thanks. Janus: Ah, so at some circumstances, they are the same. But sometimes they are not, and when they are, the can you not is more rhetorical? – Safira Dec 26 '13 at 3:51

A simple stress of the NOT in the sentence, that's all.

Can't you hear me? - am I not getting through?

Can you not hear me? - is it really true you can NOT hear me?

The is it not? is getting on a bit. A little archaic. I would not expect to hear it outside a '50s boarding school movie

  • So you're saying that can you not has a bit stronger meaning of not than can't you? – Safira Dec 26 '13 at 3:46
  • Depends on context. I would not be surprised to hear the un-contracted form used by older British people, perhaps used to more formal speech. Also as Colin answered, there is also the "can you not do that" – mplungjan Dec 26 '13 at 5:34

With parts of be and modals (can, should etc), the two forms

Isn't he, won't you, shouldn't they


Is he not, will you not, should they not

are in free variation. Some people rarely use the uncontracted forms, but others use both, with sometimes the uncontracted form being a little stronger, or just more formal.

In the case of the modals, and especially can, there is the possibility of ambiguity, because

can you not go?

which usually means "is it impossible for you to go", can also mean "is it possible for you not to go": this meaning will generally be expressed by a strong stress on not, and probably a break before it.

  • So basically they are the same? There is no different usage or something? – Safira Dec 26 '13 at 3:46

In Cumbria we often use the 'is it not'/'would you not'/'can you not' etc. version where people from the south of the Uk would say 'isn't it'/'wouldn't you'/'can't you' etc.

  • Agreed. This is a common difference between the English of the North and South of England. (I'm pretty sure it was Trudgill I read this in, but don't have it to hand. But it's easy to observe). – Dan Sheppard May 4 '14 at 14:19

I am American, south-eastern American. But my mother is a strict Grammer Nazi. So, this is how I see it:

Can't you pick up the kids from church?

This is a quick question stated in simplest terms. And it is stated in a positive way that, on its own, sounds as if the person asking it just needs clarification on something that has been previously discussed or acknowledged in some way, shape, or form.

On the other hand:

"Can you not" pick the kids up from church?

No matter which word a person emphasizes, to me, it always sounds like it has a negative tone, as if it is being said in this way in order to make a statement of disgust, disappointment, or even sorrow, instead of as a question that requires an answer.

  • That's a great example which is not merely a decontraction -- the longer version can actually mean "Please do not", The accompanying commentary is not so great. – Ben Voigt Feb 6 '19 at 17:26

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