From The Art and Popular Culture Encyclopedia
Public speaking is the process of speaking to a group of people in a structured, deliberate manner intended to inform, influence, or entertain the listeners. The art and science of public speaking, especially in a North American competitive environment, is also known as forensics. The word "forensic" is an adjective meaning "of public debate or argument." The word is derived from the Latin forensis, meaning "of the forum." The sense of the word "forensic" that means "pertaining to legal trials" dates from the 1600s (Oxford English Dictionary) and led to the use of the word "forensics" in reference to legal evidence.
In public speaking, as in any form of communication, there are five basic elements, often expressed as "who is saying what to whom using what medium with what effects?" The purpose of public speaking can range from simply transmitting information, to motivating people to act, to simply telling a story. Good orators should be able to change the emotions of their listeners, not just inform them. Public speaking can also be considered a discourse community. It contains elements of a discourse community that exist in many mediums and forms that serve different purposes for society and business among other areas of communication. Interpersonal communication and public speaking have several components that embrace such things as motivational speaking, leadership/personal development, business, customer service, large group communication, and mass communication. Public speaking can be a powerful tool to use for purposes such as motivation, influence, persuasion, informing, translation, or simply entertaining.