Why do you think the language of this speech is unusual for him? His characteristic words are peppered throughout : believe me, incredible, fantastic, amazing, impressive... His general speech habit is hyperbole, both to praise and to put down.
With what all's going on, I was half expecting something 'interesting' to happen with this speech, but he didn't oblige. I remember tons of instant reactions to the 'carnage' speech a while back. But this one , there won't be a whole lot of buzz from it.
I listened to Trump's speech at the Coast Guard Academy. The first part, which was about the Coast Guard, was well written. I suspect the president had no input to that, while the second part was him touting his accomplishments. I would love to see a discourse analysis of the speech. There is a huge contrast between the vocabulary of the two parts, the first part containing grammar and vocabulary he would never use. When he occasionally improvised a phrase it was very obvious. The second part reverted to a more simple vocabulary and grammar. I'd like to compare the words of Latin vs. Anglo-Saxon origin for the two parts.