For this subject, I analyzed famous speeches, which are especially interesting if you know the historical context and I also listened to and analyzed the speeches of their opponents, which provided additional context.
I have held a short speech for some people about Greenwich.
Tortured for Christ, by Richard Wurmbrand
Rivers of Blood, by Enoch Powell and its analysis
A time for choosing, by Ronald Reagan
Nonviolence, by Mahatma Ghandi
Peace in the Middle-East, by Golda Meir
We shall never surrender, by Winston Churchill
I have a dream, by Martin Luther King
Power! Power! Africa it is ours!, by Nelson Mandela
Inauguration speech, by Donald Trump
Osama Bin Laden killed in Pakistan, by Barack Obama
I devote my life, wether it be long or short, by Princess Elizabeth
Psychology of the masses (book) by Gustav Le Bon
I have the pleasure to know Michael Zimmermann and Graham Haddow, which are the best speakers I have personally met.