Giving a speech is an art unto itself. If you haven't done many of them before, it's tempting to write down everything you want to say in essay form and read it aloud. Business blog HBR explains why this is a terrible idea.
Photo by Renato Ganoza
Speeches are fundamentally different from essays in that the reader can only retain so many of the words you're saying. While you can fill an essay with facts and ask the reader to refer back to earlier or to re-read if they missed something, a speech is gone once the words are out of your mouth. Therefore, while repetition may be shunned in writing, it should be emphasised in speech:
Speeches require you to simplify. The average adult reads 300 words per minute, but people can only follow speech closely at around 150-160 words per minute. Similarly, studies have shown auditory memory is typically inferior to visual memory, and while most of us can read for hours, our ability to focus on a speech is more constrained. It's important, then, to write brief and clear speeches. Ten minutes of speaking is only about 1,300 words (you can use this calculator), and while written texts -- which can be reviewed, reread, and reexamined -- can be subtle and nuanced, spoken word must be followed in the moment and must be appropriately short, sweet, and to the point.
Repetition and information density aren't the only differences between speeches and essays, but understanding how the two relate (or don't) to each other can help improve your presentations.
A Speech Is Not an Essay [HBR]