staving R A Brown:

> The ancients were far more conscious of things like sound and rhythm
> than we are. When we hear, for example, a politician speaking, we are
> not likely to be thinking much at all about the arrangement of her/his
> subordinate clauses or of the rhythms of the cadences of his sentences!
> If we applaud or boo such a speaker it will be for what s/he says, not
> the way it is said.

I don't think one needs to be conscious of the poetic forms used in a 
speech for them to be effective. Consider the greatest English language 
orator of the 20th Century, Sir Winston Spencer Churchill. While one 
does not normally think of his "We will fight them on the beaches" 
speach as poetry, there it certainly makes effective use of some poetic 
devices, such as repetition with variations of a central theme.

Why is this? Good oratory has to stick in the mind. I think it is likely 
that poetry originally arose as a means to aid the memorisation of oral 
narratives - for example, Homer's epics were transmitted orally for 
centuries before they were written down. Good poetry is easy to memorise 
- if you read through AA Milne's poem "Teddy Bear" a few times you'll be 
able to recite it from memory without difficulty. So, if you want to 
make a speech that will stick in people's minds, you write it a bit like 
poetry. Your audience doesn't have to know that you're doing it for it 
to work.