Extemporaneous informative speaking: The purpose of an informative speech is to stimulate and interest in current affairs. You will need to present information orally in an interesting, but impartial way, and use the best resources available to you to gather facts.
Extemporaneous persuasive speaking: The purpose of a persuasive speech is to sway listeners to the stance of the speaker. You will need to analyze an issue and then organize a speech with the aid of sources to reinforce this belief in those who share this viewpoint and attempt to persuade others with opposing viewpoints to change their stance.
Extemporaneous group communication/presentations: The goal of group communication/presentations is that same as persuasive speaking, but with an addition of more people participating! The speakers develop a persuasive speech on a policy to gain immediate action or passive agreement, but only requires a consensus for an agreement. Presenters can show their findings in different ways - reports, discussions, ect.
Speaking to entertain: The purpose of speaking to entertain is just that, speaking to amuse an audience while delivering a message. Just like the previous types of speeches, there should be a clear message that is delivered, but the manner of speaking is usually different. These speeches are usually given at special events such as acceptance speeches or weddings and are designed to emotionally arouse the listeners in some way. Entertain can mean humor, but it could also mean drama. This type of speech is generally the most common one we see in our everyday lives.
The following resources can be used to help you select a topic. Locate a topic that you find a personal interest in to ensure that its engaging for your audience as well. The resources below can help you choose popular, contemporary topics.