Public speaking (also called oratory or oration) is the process or act of performing a speech to a live audience. This type of speech is deliberately structured with three general purposes: to inform, to persuade and to entertain. Public speaking is commonly understood as formal, face-to-face speaking of a single person to a group of listeners.
There are five basic elements of public speaking that are described in Lasswell's model of communication: the communicator, message, medium, audience and effect. In short, the speaker should be answering the question "who says what in which channel to whom with what effect?"
Public speaking can serve the purpose of transmitting information, telling a story, motivating people to act or some combination of those. Public speaking can also take the form of a discourse community, in which the audience and speaker use discourse to achieve a common goal.
Public speaking for business and commercial events is often done by professionals. These speakers can be contracted independently, through representation by a speakers bureau, or by other means. Public speaking plays a large role in the professional world; in fact, it is believed that 70 percent of all jobs involve some form of public speaking.
Although there is evidence of public speech training in ancient Egypt, the first known piece on oratory, written over 2,000 years ago, came from ancient Greece. This work elaborated on principles drawn from the practices and experiences of ancient Greek orators. Aristotle was one of the first recorded teachers of oratory to use definitive rules and models. His emphasis on oratory lead to oration becoming an essential part of a liberal arts education during the Middle Ages and the Renaissance. The classical antiquity works written by the ancient Greeks capture the ways they taught and developed the art of public speaking thousands of years ago.
In classical Greece and Rome, rhetoric was the main component of composition and speech delivery, both of which were critical skills for citizens to use in public and private life. In ancient Greece, citizens spoke on their own behalf rather than having professionals, like modern lawyers, to speak for them. Any citizen who wished to succeed in court, in politics or in social life had to learn techniques of public speaking. Rhetorical tools were first taught by a group of rhetoric teachers called Sophists who are notable for teaching paying students how to speak effectively using the methods they developed.