the Way You SAY It.
Once speakers find a line they can remember, it gets anchored into a certain style, and they will end up speaking it the same why time after time. Unfortunately, this doesn't always serve them well. It can be easy to simply be happy you are remembering what you want to say, instead of also focusing on HOW You Want To Say It.
If you aren't examining where you're putting the EMphasis in your EmPHAsis, you are likely robbing yourself and your audience of some of the power of your message.
How do you police yourself? It's easier than you think, and can actually be a lot of fun!
First, record your speech, and listen to it - just LISTEN - and hear where you are losing power. Ask a coach or friend for input on this as well.
Second, record yourself again, using different voices - cartoon voices, voices with accents, loud voices, quiet voices - go crazy. Give it in monotone, give it as the guy who narrates movie trailers, give it as Lily Tomlin. Go slow. Go FAST - CRAZY fast.
You can do this for the whole speech, or vary within a single practice or two.
This helps you in two ways - A. It stretches your mind and voice, allowing you to be freer as a speaker, and B. It can point out places saying a word or phrase with a different emphasis, speed, cadence, or amplitude will help bring it's full power to the audience.
After you get loosened up by making a fool of yourself a few times, go in to your script and pick out what you think are your power phrases, those words you want the audience to hang on to, and focus this method on them, until you find EXACTLY the way you want to SAY it for maximum effect.
Ironically, it is in our process of memorization that we create bad habits in the way we SPEAK our speech, and it is in THIS process of recalibrating how we say it that we can re-anchor our words and BETTER memorize it than ever before.
Have fun with yourself - be willing to sound idiotic in the privacy of your own house, car or shower. In the long run you, and your audience, will be glad you worked just a little bit harder to SPEAK...and Deliver.