inviting people to speak
(Paul), you had something you wanted to say.
What's your opinion?
What do you think?
ways of agreeing
That may be true, but what about....?
Yes, I'd agree with that.
ways of disagreeing
That's not true, actually.
Well, I'm not sure about that.
I'm not sure I agree, actually.
asking to speak
Sorry, do you mind if I interrupt?
Can I just say something here?
allowing someone to interrupt
Sure, go ahead.
Yes, of course.
not allowing someone to interrupt
Can I just finish what I was saying?
If I could just finish making this point.