Every speech or presentation should be built around one idea. Just one idea. But it has to be a "Big Idea." Something that appeals to people's intellect, emotions, and imaginations. Something that has the power to change people's lives, if only in a small way.
I've found over the years that there's an inverse correlation between BIG WORDS and BIG IDEAS. The bigger the words used in a speech, the smaller the idea.
If your idea is big enough to stand on its own two feet, you don't have to inflate it with big words.
But if you doubt the value or the power of your idea, you might try to make it sound more impressive that it is by using words like incentivize, bottom line, ROI, going forward, robust, stakeholder, low-hanging fruit, granularity, and 360-anything.
George Orwell, the English essayist and author of 1984 and Animal Farm, created rules of effective speaking. They apply equally well to effective speaking.
Orwell's 5th rule – "Never use a foreign phrase, a scientific word, or a jargon word if you can think of an everyday English equivalent" – says the same thing I'm proposing.
When you speak – no matter what size audience you're addressing – choose words that are clear, specific, and concrete. Say what you means as simply and directly as possible.