Okay here is the topic: What is the difference between No, It's not. vs No, It isn't... I think it's just a matter of emphasis but want to make sure.

Here's a couple links about it:

http://www.languagehat.com/archives/001969.php




If the above link doesn't suit your likening, try this 40 page dissertation:
http://www.stanford.edu/~dialect/yaegeretal2002.pdf

Well, before reading what others said in those threads, I'll take a stab.

I feel that 'It's not.' is focussing on the predicate not being right. Where 'It isn't.' places emphasis that the subject is wrong. Of course we're splitting hairs here. I don't think that there's much need for an L2 speaker to have to know the difference. (We don't and it wouldn't matter which one you used in most situations.) However take a look a these simple exchanges.

S1 picks up a bag sitting in the room and simply has a question for S2:

S1: Is this yours?
S2: No, it's not.
S1: Hmm? I wonder whose it is.

S2 is looking for his pen. S1 finds a pen and asks:

S1: Is this it?
S2: No, it isn't.
S1: How about this one?
...

Maybe I'm just making stuff up. ... Actually, naturally the answer to both of those questions would just be 'No.'

After thinking about it a bit, I don't think you could really postulate a rule between the two because the language would fail to always follow it. Since there's no equivalent form when the subject is 'I', your rule would fail in all instances with 'I' as the subject.

Of course you could make 'I' an exception but generally when a rule gets 'ugly' with exceptions and stipulations, you've generally gotten the rule wrong or there isn't a rule.

Thanx Patrick.... Mark that was my thought too. but had to be sure... thanx for the input...

I never really thought about there being much of a difference.

A lot of the books I teach with use"No it isn't."

I've always tended to use "No, it's not." because there are less sounds in the statement and most of my students are young low level learners.

Maybe the contraction would change depending on the grammar point you're specifically focusing on?

Meaning, if you are teaching be-verbs, you want to see the verb so you might favor using, "No, it isn't."

Alternatively, if you were focusing on negatives, you might favor, "No, it's not."

I agree that there's no real, reliable rule to differentiate the two.

With beginners, I generally think it's better to stick to "No I'm not", "No he's not" etc. as it's the more logical and consistent version, and then hit them with the alternative ("No he isn't") a little later. Introducing the two at the same time could cause confusion.

But it could also be argued that both should be introduced at the same time, since both are used with roughly equal frequency.

I guess there are no easy answers on this one.