Role of the Speaker, Chair & Questioner
The Speaker: Makes the speech on behalf of the team. The speaker then listens very carefully to the questions posed by both the opposite team and the floor.
The Chair introduces the team and tells us a bit about them. The chair then coordinates the session, calling for questions, thanking the audience and making a summary.
The Questioner listens very carefully to the other team's speaker. The Questioner thanks the speaker (by name) and poses well constructed questions.