Speaking Effectively

Supposing someone did ask you to do this. How would you react? Would you go along and just trust to luck that the right words would occur to you when you needed them? Or would you plan your approach? If the boss didn’t give in easily to your request, would you become aggressive? Or would you keep calm? If Dave wasn’t presenting a very good case, would you butt in impatiently and take over? How do you estimate your ability at effective speaking? Not just the formal occasion but in face-to-face discussions and interviews, at meetings and on the telephone? but in face-to-face discussions and interviews, at meetings and on the telephone?