It's obvious when he's reading from a prompter or vamping. His rallies are pure off the cuff vamping (rambling). I can guarantee the speech writers don't include the kind of language that he uses when vamping.Trump himself should be fined for swearing during his speeches. He is obviously one of the most un presidential presidents in history and I believe history will regard him as such. Would not be suprised if it is his speechwriters and advisors that are telling him to speak like this to keep that kind of rhetoric going and keep him controversial because they think people like that for some reason.