There are four basic types of speeches according to purpose: to inform, to instruct, to persuade, and to entertain. You may have one specific purpose or a combination of any of these objectives when giving your presentation. For example, you may try to inform in an entertaining style or inform as you entertain your audience. Another speaker, say an advertiser or a politician, might inform the audience and try to persuade them to act on the information. However, the overriding purpose of a speech will generally fall into one of these types:
Informative
This speech serves to provide interesting and useful information to your audience, like your teacher talking about earthquakes or a fellow student presenting his/her research. In paper/research presentations or academic forums, speakers aim to give significant information to the audience.
Demonstrative
This has many similarities with an informative speech, but it also teaches you to do or perform something. A cooking demonstration is a good example of this kind of speech, which instructs the audience on how to do something step by step. Have you gone to big malls where they demonstrate how to arrange flowers or decorate cakes and cookies? Notice that the speakers or demonstrators deliver their respective speech while demonstrating or performing the process.
Persuasive
A persuasive speech aims to persuade or convince people to change the way they think or do something, or to start doing something that they are not currently doing. Most political speeches aim at targeting the belief system of the listeners. They can make the audience laugh, like, love, want, or desire a specific change or make them reject or hate a policy, program, service, or even an institution or other people. Talks on becoming an organ donor or improving your health through better eating are simple examples.
Entertaining
The speech during a program intermission or after dinner is a typical example of an entertaining speech. The speaker provides pleasure and enjoyment that make the audience laugh or identify with anecdotal information. The toastmaster speech is known to have such characteristics. Have you tried speaking at your friend’s birthday party? The invited speaker is usually a person full of pep. She/he can entertain the guests and make the party atmosphere pleasant.