I’m continuing a series of public speaking principles in the next few blog posts that are a summation of what I’ve learned about this fiendishly difficult art and science over three decades of practice, coaching, learning from others, and research, especially neuroscience.  Here are the next seven, concerning the content of a great speech.

36.A great speech opens the audience to wider territory at the close. Speeches should move audiences to action, of course, but they should also encourage audiences to think more broadly at the end, rather than closing down. For example, President Kennedy’s great speech launching the Apollo program to the moon, concluded with asking for “God’s blessing on the most hazardous and dangerous and greatest adventure on which man has ever embarked.”

37.A great speech should be simple in structure and rich in detail. The best way to develop a speech is to break it down into five or fewer main sections, which you develop at the level of detail that the subject demands and time permits. You should have the structure memorized but not the exact flow of the details, in order to give the speech a conversational feel.  Very few speakers can deliver a completely memorized speech effectively.

38.Good speeches present complicated subjects with all their complexity. Great speeches present complicated subjects with simplicity.  That sort of simplicity is the hard-won wisdom of knowing the difference between the essential and the merely important – the wisdom that comes from deep expertise and experience in a field.

39.A speech can persuade, it can teach, and it can motivate, but it can’t do all three. It’s no accident that motivational speeches often leave their audiences wondering what was said.  An emotion was conveyed, but little was taught.  Similarly, a speech that teaches a method or a system rarely causes audiences to leap to their feet.  The emotional ground that persuasion, teaching, and motivation cover is too broad to manage all three at once.  Pick any two to be successful.  Focus on one to be truly world class.

40.If you can’t give your speech to your children or grandchildren and hold their attention throughout, you’re not ready to speak yet. You should know your speech well enough so that, if you need to simplify it a bit to hold the attention of a young person, you can do that without destroying the structure and flow of the speech. Better yet, pitch it at their level to begin with – up to a point, of course.

41.For those speaking globally, your content will need to vary by culture, but your body language should stay the same. One of the great misunderstandings about body language is the extent to which it is universal.  There are cultural differences, of course, but body language is integral to your consistent delivery, and should not shift hugely from one place to another.

42.The length and tone of your speech should vary depending on the time of day it is given. The later in the day the speech is scheduled the shorter it should be, and the lighter in tone. There are, of course, exceptions to this rule – State of the Union addresses by American Presidents, for example.  But fewer than you might think.

My goal in these principles is to explore the implicit rules of public speaking, the kind people rarely bring up in lists of the 10 rules for public speaking, which almost all start with “follow your passion” and end with “always end on time.”  Both are true and good bits of advice, but they don’t help speakers much beyond the absolute beginning steps.