C'est pas grave

[Jim606185]

Every time I've heard a native speaker say this, he or she says "c'est pas grave" instead of ce n'est pas grave. I used c'est pas grave in a Duolingo exercise and was marked wrong.

Is this considered grammatically correct or is it just a colloquial thing that a lot of people say, like ouai, ché pas, j'ai kiffé ça etc ? Duolingo doesn't like j'ai kiffé either.

To what extent is this sort of thing used in casual conversation. Is it an informal register only or is it more general?

The extended French from English course is a lot of work, but I'm getting there. I really like the Italian from French course too. It's much better than Italian from English.

[vero-bis]

It is not grammatically correct. It is an informal register and it is much used.
You can also hear "c'n'est pas grave".

[Cifi]

Is Duolingo actually teaching sentences with "ne" dropped (I feel the shouldn't, at least not in the first few lessons)?

I came across "C'est pas facile tous les jours" in a "Read and respond" exercise today.

Grammatically correct would be "Ce n'est pas facile tous les jours", right?

[BlahBlah]

In regular, everyday speech, "ne" is dropped very often. It's not correct, but it's how a lot people speak.

For example, "je ne veux pas" becomes "je veux pas".
Then you have "je ne sais pas", which not only becomes "je sais pas" but even "chais pas".*
Or "je suis" which becomes something like "joui"... Check out Memrise French course, it's full of examples of everyday speech.

*You can hear that in the chorus of a famous Maître Gims song. https://www.youtube.com/watch?v=6TpyRE_juyA
("chais pas" si je t'aime)

[Cifi]

Yes, I understand it is used a lot, but I still think it would be preferable to teach beginners the grammatically correct form first.

Or, if that is part of their teaching concept, they should accept "je sais pas" instead of "je ne sais pas", which I think they don't.

[Cifi]

Or, if that is part of their teaching concept, they should accept "je sais pas" instead of "je ne sais pas", which I think they don't.

I tested it and can confirm they reject "je sais pas".