2
1
In the following set of pairs, the first part of the pair is the standard negative form of contraction.
Are they ever heard of in conversations? If yes, are they as acceptable as the standard contracted forms?
He hasn't come yet. He's not come yet
He hasn't been working. He's not been working
They haven't come yet. They've not come yet
They haven't been working. They've not been working
Update: You can read more about less common contractions in the following posts:
1As far as I can tell, when the not part is not contracted, it means that the speaker wants to emphasize the "not". (This might be clearer and more obvious when we actually hear them. The prosody will make it so obvious.) However, one important note is the contraction of "have" when it's used as the main verb should be avoid, e.g. avoid this: "They've two cars." – Damkerng T. – 2014-01-14T13:09:36.603
1+1 You have brought up very interesting points. I've just checked with COCA to find out that there are many citations to the "he's not been" in SPOKEN English. I cannot commit myself to detailed research now, so I'll put it on the back burner. I think I can check avoiding contracting have when used as a main verb. I've always wanted to check that. – learner – 2014-01-14T15:03:30.273