Speeches are awesome in that they differentiate people the best in my belief. If you can't write, then you can't write a speech. If you can write an essay, that doesn't mean you can write a speech.
Speeches differ from any other text type in that they engage the emotions and rally people to a cause. Doing that requires skill, control and flair in the words you choose, the way you arrange the words and the way the words are meant to be said. Really, that art of rhetoric is something you can't really fake - I think.
Read it out loud and see if it's rallying and a good speech. You know one when you hear one.