The pioneer scholastic work on the art of speaking was in Greece at around 1600AD. An elaborate set of principles was developed mainly drawn from the experience and practices of famous Greek orators at the time. Though these basic principles have been transformed over the years and modified to fit in with the times, the three fundamental tenets of public speaking remain solidly rooted in these pioneer principles.
The first tenet is oratory, and it refers to an ancient art of public speech. Oratory was practiced in Greece and Rome during their respective civilizations and studied as a component of rhetoric. This tenet has definite rules and models emphasized by the liberal arts since the Renaissance and Middle Ages. Oratory has significance in public speaking because it constitutes the composition and delivery of speeches.
The second tenet is that of using extra linguistic features other wise called gestures as accompaniment to speech. What a person says is equally important as what he does while doing it. The motivational speakers skills entail conscious use of facial expressions, hand movements, body postures and other gestures as accompaniments to the spoken message.
Control of the voice through intimate inflection is the other key tenet, which makes a public speaker either boring or interesting to listen to. How one combines the lows and the highs in the voice quality, the soft and the deep, the appeals and commands etc. determines the effect of public speech to the audience.
There are other key principles of public speaking that are included as additions of the basic three exemplified above. These include command of an impressive vocabulary inventory from which an appropriate register is handpicked with a precise and deliberate word choice, the relevant and sensitive use of humor in speech and the use of speaking notes as preferred over reading word-by-word speeches.