Do we tend to speak rhythmically when we want to emphasize something?

If someone declares This is impossible, does it tend to be said in iambic pentameter (pairs of unstressed and stressed syllables)? What about He who laughs last laughs best. What about the Gettysburg address?

If you say, What goes up must come down, does your voice rise slightly in pitch for the first three syllables and fall for the second three?

John Kennedy famously said, Ask not what your country can do for you. Ask what you can do for your country. It is a noble sentiment, but does not lend itself to any rhythm. It might be repeated more often if it did. Does Trump’s speech pattern sound like something from Dr Seuss.