What technological advancement most strongly affected a leaders speech during world war 2?

One of the most significant technological advancements that affected leaders' speeches during World War II was the widespread use of radio broadcasting. This allowed leaders like Franklin D. Roosevelt and Winston Churchill to reach large audiences directly and instantly, making their messages more immediate and personal. The ability to broadcast speeches live enabled them to rally public support, boost morale, and communicate important wartime messages effectively. Additionally, the use of film and newsreels helped to amplify their speeches visually, further enhancing their impact on the populace.