it's not/it isn't

[olivierfouquet2000]

> Sophie wrote:
> 
> 
> Here's a question for all you native English-speakers. I've long 
wanted to know the answer to this question, but it only recently 
occurred to me to try my luck on this list:
> 
> Is there any difference in tone and or usage between saying "it's
> not" and "it isn't"?
> 
> Paula now:
> 
> You know, now that I think of it, this is probably one of those 
things discussed in a  linguistics PhD thesis somewhere...
> 

Olivier now:

And right you are Paula to think so. This has been indeed discussed 
by Steven Pinker and more extensively by at least another linguist I 
can't remember the name right now. However, the distinction does not 
have anything to do with tone and usage but rather with the syntax of 
the auxiliary in English, usage is treated as an entirely 
conventional things in these works. The same studies show why you can 
say "I'm french" but not "Are you french? Yes, I'm" even though the 
meaning would be perfectly clear.

Olivier