Some will even tell you to pay attention to great movies, and follow their rhythms and methods in great storytelling. Just be careful which movies you watch, or you might end up with a bloated and ridiculous speech where the overall point gets completely lost.
I know I'm getting old - just turned (shudder) 43 this month, so I guess I'm now officially middle-aged - but I still love books. And I find my greatest inspiration for speech-writing style in the books I've read over the years. Some are books written for adolescents, some for adults who still want to be. All are, to me, great examples of storytelling, and offer strong examples of character development, dialogue, setting, making a point with subtlety, humor devices, and even audience connection (though rarely all at once...).
A great speech - a REALLY GREAT speech - starts out in written form most of the time. I'd venture to say most means 95% in this case, or more, though that can be considered a MUFBOMNSHP (made up fact based on my not so humble opinion). So why not study the written word?
Below are some books that have strongly influenced my style of writing. For the record, I'm not trying to make any money here - all links are non-affiliate.
The Great Brain by John Fitzgerald - a wonderful kids series that takes place in the 1890's. Definitely fostered creativity, an appreciation for historical settings, as well as sarcasm and irony.
Dandelion Wine (and most anything else by Ray Bradbury) - This book featured strong characters and offered great examples of whimsical and motivational themes without beating me over the head as I read them. The Illustrated Man is a close second in my Bradbury collection.
Lake Wobegon Days by Garrison Keillor - this was assigned to me in college, and I absolutely loved it. The style, the humor, the matter-of-fact character descriptions all wrapped up in midwestern charm has influenced my speechwriting from the beginning. It was years later I realized he was a radio personality and well-received speaker, as well.
What about you? Reading is recommended by most any coach, speaking, life, business, or otherwise. It's easy to get caught up in the latest business or self-help tome, but as speakers, we may be best served by delving into fiction, or at least fictionalized history. What do you read? Who are the authors who have influenced you the most?