ASKING FOR SPELLING
Could you spell that, please?
Would you mind spelling that for me, please?

Asking for Contributions

We haven't heard from you yet, (name of participant).
What do you think about this proposal?
Would you like to add anything, (name of participant)?
Has anyone else got anything to contribute?
Are there any more comments?

Correcting Information

Sorry, I think you misunderstood what I said.
Sorry, that's not quite right.
I'm afraid you don't understand what I'm saying.
That's not quite what I had in mind.
That's not what I meant.