Americans often say that they fear taxes, death, and public speaking. It's a strange combination of fears. This is especially true since most elementary schools, high schools, colleges, and universities in America provide many partial or full courses in public speaking. Many universities require every student to take a course in public speaking. In American business, the Dale Carnegie Company and the volunteer Toastmasters offer much training in public speaking. So, why do so many Americans fear giving public speeches? Perhaps, they fear seeming to be foolish in front of others, or lack confidence in their own abilities.
As early as the fifth century before the birth of Christ or the common Era, Plato, Aristotle, and other famous Green teachers were training young men in effective public speeches as a standard part of becoming a good citizen in their society. Aristotle said that every speech is like a human body, with a head (introduction) body (development of the main ideas), and feet (conclusion). Rhetoric, seen then as "finding all of the available means of persuasion" has had a 2500 year history for the effective preparation and presentation of oral and written messages. Aristotle's three major proofs in rhetoric have remained useful even now: ethos  he credibility, knowledge, and good will of the message presenter, logos  the construction of arguments and threir support through reliable evidence, and pathos-the emotional appeals which can be make to members of an audience which will move them toward belief or action.
In modern persuasion, the message givers are interested in identifying values which they support, the maintenance or change of policies; refutation of opposing arguments, and advocacy for sustaining or changing beliefs, and calling people to specific forms of action.
Today, there are many thousands of public speaking courses in America. Thousands of public speeches are given annually. A US presidential election finds the candidates of the major parties giving perhaps a dozen speeches a day for many months.
On a personal level, I always have had great confidence in myself as a public speaker. I involved myself in speaking contests in high school, was a university debator, and have sometimes given dozens of speeches a year as a university professor. Naturally, I also give many lectures or mini lectures in my classes over more than 40 years of university teaching. I tell my students that good public speaking requires a good sense of the topic, an interest in the topic, good research on the topic and lots and lots of experience. In this way, practice can make perfect, if on practice toward a sense of personal excellence in public speaking. In China, I have given many speeches, and would much prefer giving speeches on topics that I know and like, than doing many other activities. You say that you want to give a speech to your group? All right, when?