It seems like in most examples the imperative forme is follow by genitive but could anyone explain to me why "innego" is it because of coś??
It just is. It's better to remember it. For some time I wasn't even sure if it's Accusative or Genitive (I would write that the most important thing is that it ends with -ego), but right now I think it has to be Genitive.
The main answer is "Say something else". "Tell" doesn't really work without "to whom", at least in the "powiedzcie" meaning.
Is this literal? Like, you just said something, could you please say something else? Or has it got another meaning ("please stop talking about that, let's talk about someting else" maybe)?
Thank you very much Jellei. I've noticed you are always very active and helpful in these comments, it makes learning Polish quite a bit easier!
Yes it sounded a bit strange to me too, like the kind of thing you would say if you wanted someone to change the subject.