Final answer:
The purpose of a speech that attempts to change listeners' attitudes, beliefs, or behaviors or encourages them to act is to persuade. Persuasive speeches use emotional, logical, and credibility appeals to influence the audience.
Step-by-step explanation:
When a speaker attempts to change listeners' attitudes, beliefs, or behaviors or motivates them to take action, the purpose of the speech is to persuade. Persuasive speech involves convincing audience members of something or influencing their beliefs, values, or behavior.
This type of speech may reinforce an audience's existing beliefs or encourage them to adopt new ones. Persuasive speeches make use of appeals to emotion (pathos), logic (logos), and credibility (ethos) to effectively convince the audience to consider the speaker's viewpoint or take the desired action.
An example of a persuasive speech is a presentation intended to convince the audience to reduce their use of disposable plastic. The speaker would craft their argument with a clear understanding of their audience, use supporting evidence and appeals to emotion, and provide a sound conclusion to effectively achieve their purpose.