How can good posture affect an impromptu speech?

Good posture plays a significant role in the effectiveness of an impromptu speech by enhancing the speaker's confidence. When a speaker stands or sits up straight, it not only projects a sense of authority and credibility but also positively influences the speaker's own feelings of self-assurance. Good posture allows for better breathing and vocal projection, which can improve clarity and make the delivery more engaging for the audience. By looking more confident, the speaker is likely to engage the audience more effectively, leading to a stronger impact of the message being conveyed.

Other options suggest that posture either has no impact or is distracting, but in reality, a confident stance can improve communication, while staying seated is less related to the benefits of posture in terms of speech delivery.