The emotions of the speaker and the listeners are alike aroused. This recommendation addresses a requirement as frequently unmet today as it was in Churchill’s 19th century day and even before that: to align the speaker’s goals with those of the audience. A speech or a presentation is not a broadcast or podcast. The essential scaffold of rhetoric is a two-way street. It’s not just about you, it’s all about them.

This would present a serious difficulty if the diarists had only reported their own thoughts, but in fact they also reported the opinions of others around them. […] Of course, those who disliked Churchill may have been biased in terms of what they recorded. But, crucially, some people who did like Churchill’s speeches recorded that others didn’t, and expressed their surprise at this. Taken in combination with survey evidence – with which they often correlate – diaries can be a potent source. Although they cannot by themselves provide definitive evidence of how many people held a particular opinion about Churchill’s speeches, they do give a good illustration of the range of views that were held. (pp. 8–9)
Of this I am quite sure, that if we open a quarrel between the past and the present, we shall find that we have lost the future. Therefore, I cannot accept the drawing of any distinctions between members of the present Government. It was formed at a moment of crisis in order to unite all the Parties and all sections of opinion. It has received the almost unanimous support of both Houses of Parliament. Its members are going to stand together, and, subject to the authority of the House of Commons, we are going to govern the country and fight the war. It is absolutely necessary at a time like this that every Minister who tries each day to do his duty shall be respected; and their subordinates must know that their chiefs are not threatened men, men who are here today and gone tomorrow, but that their directions must be punctually and faithfully obeyed. Without this concentrated power we cannot face what lies before us. I should not think it would be very advantageous for the House to prolong this debate this afternoon under conditions of public stress. Many facts are not clear that will be clear in a short time. We are to have a secret session on Thursday, and I should think that would be a better opportunity for the many earnest expressions of opinion which members will desire to make and for the House to discuss vital matters without having everything read the next morning by our dangerous foes.
The famous June 1940 speech “We shall fight them on the beaches, we shall fight on the landings grounds, we shall fight in the fields and in the streets, we shall fight in the hills; we shall never surrender,” was influenced by William Philip Simms, the pro-British foreign editor of the influential Scripps-Howard chain of American newspapers.  There was concern that the USA would not enter the war, so Simms provided suggestions that were passed on to Churchill, to advise on the language needed to maximise Americans’ sympathies in the war, so that they would support and get behind the British.  In order to scotch the growing belief that the Allies could not take much more punishment, he argued that Churchill should say something on the following lines:
In the rush to disarmament, “conditions were swiftly created by the victorious Allies which, in the name of peace, cleared the way for the renewal of war . . . . The crimes of the vanquished find their background and their explanation, though not, of course, their pardon, in the follies of the victors. Without these follies crime would have found neither temptation nor opportunity.”

Turning once again, and this time more generally, to the question of invasion, I would observe that there has never been a period in all these long centuries of which we boast when an absolute guarantee against invasion, still less against serious raids, could have been given to our people. In the days of Napoleon the same wind which would have carried his transports across the Channel might have driven away the blockading fleet. There was always the chance, and it is that chance which has excited and befooled the imaginations of many Continental tyrants. Many are the tales that are told. We are assured that novel methods will be adopted, and when we see the originality of malice, the ingenuity of aggression, which our enemy displays, we may certainly prepare ourselves for every kind of novel stratagem and every kind of brutal and treacherous maneuver. I think that no idea is so outlandish that it should not be considered and viewed with a searching, but at the same time, I hope, with a steady eye. We must never forget the solid assurances of sea power and those which belong to air power if it can be locally exercised.
The disastrous military events which have happened during the past fortnight have not come to me with any sense of surprise. Indeed, I indicated a fortnight ago as clearly as I could to the House that the worst possibilities were open; and I made it perfectly clear then that whatever happened in France would make no difference to the resolve of Britain and the British Empire to fight on, if necessary for years, if necessary alone.
The German breakthrough had not been exploited southwards, and the French had improvised a relatively thinly held defensive line along the Aisne and the Somme. The British military evaluation was that this was unlikely to withstand any major attack by the Wehrmacht. In the air, the French were short of fighter planes and the shortage was worsening due to their many losses in combat. The French military commanders had hence asked for additional British fighter squadrons to be sent into the fight in France. Politically, there were considerable doubts over the French willingness to continue the war, even in the absence of any further military catastrophes. Churchill had argued in favour of sending the fighter squadrons to France because he considered that that move would be vital to sustain French public morale, and also to give no excuse for the collapse of the French Army. That would possibly lead to a French government that would not only drop out of the war, but also become hostile to the United Kingdom. The British War Cabinet discussed this issue at meetings on 3 June and on the morning of 4 June, but it decided to take the advice of the Royal Air Force and the Secretary of State for Air, Sir Archibald Sinclair, that the British priority must be to prepare its own defences. The three squadrons present in France would be kept up to fighting strength, but no further squadrons could be spared for the Battle of France.[4]

Upon this battle depends the survival of Christian civilisation. Upon it depends our own British life and the long continuity of our institutions and our Empire. The whole fury and might of the enemy must very soon be turned on us now. Hitler knows that he will have to break us in this island or lose the war. If we can stand up to him, all Europe may be free and the life of the world may move forward into broad, sunlit uplands. But if we fail, then the whole world, including the United States, including all that we have known and cared for, will sink into the abyss of a new Dark Age, made more sinister, and perhaps more protracted, by the lights of perverted science. Let us therefore brace ourselves to our duties, and so bear ourselves that, if the British Empire and its Commonwealth last for a thousand years, men will still say, 'This was their finest hour.' 

We shall go on to the end, we shall fight in France, we shall fight on the seas and oceans, we shall fight with growing confidence and growing strength in the air, we shall defend our Island, whatever the cost may be, we shall fight on the beaches, we shall fight on the landing grounds, we shall fight in the fields and in the streets, we shall fight in the hills; we shall never surrender.”
Churchill’s “Iron Curtain” speech at Fulton, Missouri, on March 5, 1946, ranks as one of the most famous and consequential speeches ever made by someone out of high office, comparable in its force to Lincoln’s “House Divided” speech of 1858 and Martin Luther King’s “I Have a Dream” speech of 1963. It is remembered as the announcement to the world of the beginning of the Cold War, although as Churchill knew the seeds had been germinating for some time. It crystallized the new situation facing the United States and Western democracies and also forecast how the new and unusual “cold” war should be conducted so as to avoid World War III and achieve a peaceful future.
"From Truman's point of view, the speech was important because the geopolitical situation had changed so much with the defeat of Nazi Germany and the new threat from the Soviet Union," Muller says. "It was somewhat easier to have Churchill, the great English-speaking ally of the United States from the war, to come and warn about the danger from the Soviet Union and from communism than for Truman to do it himself... It wasn't completely original. There had been various observers of foreign affairs who had suggested that this change was about to happen but from the public's point of view, it was really a startling change." 

Churchill persevered and worked on his pronunciation diligently, rehearsing phrases such as “The Spanish ships I cannot see for they are not in sight”. He tried to avoid words beginning and ending with an ‘s’, but when he did, his pronunciation became a part of his intonation and oratory, later mispronouncing “Nazis” as “Narzees” to great effect and advantage.
To make note of the complexity of the origins and responses to this wonderful speech by no means implies criticism of Churchill. Rather, it prompts us to rethink the factors that contributed to his oratorical success. He did not merely provide uplifting soundbites; he presented a factual and reasoned case, provided the public with new information and, crucially, provided them with the context necessary to understand it. He was willing to run the risk of depressing his audience if this would serve the greater purpose of bringing them into contact with reality; he did not attempt to win easy popularity by providing false hope. He followed this formula throughout the war, not always with complete success in terms of audience response, but with the ultimate achievement of establishing his credibility as someone who would deliver the facts no matter how unpalatable they might be. This is a lesson which modern orators will do well to follow.
Nevertheless, our thankfulness at the escape of our Army and so many men, whose loved ones have passed through an agonizing week, must not blind us to the fact that what has happened in France and Belgium is a colossal military disaster. The French Army has been weakened, the Belgian Army has been lost, a large part of those fortified lines upon which so much faith had been reposed is gone, many valuable mining districts and factories have passed into the enemy’s possession, the whole of the Channel ports are in his hands, with all the tragic consequences that follow from that, and we must expect another blow to be struck almost immediately at us or at France. We are told that Herr Hitler has a plan for invading the British Isles. This has often been thought of before. When Napoleon lay at Boulogne for a year with his flat-bottomed boats and his Grand Army, he was told by someone. “There are bitter weeds in England.” There are certainly a great many more of them since the British Expeditionary Force returned. 

Winston Churchill Speech WW2