the mind > language > speech > speech-making > [noun] > one who makes a speech or speeches > for specific occasion, purpose, or cause (4)
A public speaker; spec. a person employed to attract custom to a show, a shop, etc.; a barker.
a person who gives a keynote speech or address.
a person who speaks from a soap-box.
A person who sets the prevailing tone for something. Now usually: a keynote speaker at a conference, political meeting, etc.