"Broadly speaking, the short words are the best, and the old words best of all. "
-- Sir Winston Churchill
Well, that's William Churchill's thought.
My thoughts ...?
Broadly speaking of course.
Keeping it simple always works in any endeavour including in public speaking, but short varied with long will have more power.
Old words - ah that appeals. There is so much less chance of misunderstanding, and people feel comfortable with the familiar.
And here is Churchill using the rule of three for great power, not to mention repetition and building to a climax.
Love it!!