“American” sounds more “A meer ecan” than “A mare ecan” to me, when she says it. I pronounce it more like the latter, and she pronounces it more like the former.
I heard a clip of MO the other day and noticed a long ‘ah’ (Ogden Ave = Aahgden) followed by a hard R (Cermak Ave = CeRrmahc) that I’m proud to associate with Chicago. Wish I could remember the clip or even just the word.
Here’s her DNC vid:
Couple exshtrordinaries in there and some hard R’s heard beginning around 2:20.
“How blessed we aRe.”
“SeRRving as your FiRRst Lady is an AhnorR.”
3:20 “grammAHs house”
6:10 “coAhllege”
6:25 “fell ShoRt”
I started a thread about this a while back. Oh wait, it was this one!
Ooooh. Double Zombie!
Thee On’r’abull Firss Lady Might’a Hadd’a couple, two, tree before da filming.
Cut her a little slack, jeez O’peete.
What’s freeky, is when your reading through a thread with something to say and suddenly realize that you’ve ninja’d yourself.
What would be truly horrifying would be if you start to read a thread and notice that the statements made in it sound distinctly out of date. You look at the date and realize that it’s a zombie. In fact, it’s from 1999 and is now thirteen years old. You continue to read the thread anyway and find a post that’s not just out of date but was stupid and misinformed even when it was written. You decide that this post has to be answered, even though it’s that old. You have most of your reply worked out in your mind when you look at the right for the name of the author of that post. You only then notice that you wrote that post.
No, it hasn’t happened to me yet, but it’s only a matter of time.
I often need to ask Aussies or Brits or Black Americans to repeat what they said. I knew someone from Missouri who said many words “wrong.” There’s a distinctive Boston accent, and a distinctive Brooklyn accent. But the linked-to Youtube?? 
I suppose within the several sentences there may be one consonant that sounds slightly irregular if you listen intently for it. If I close my eyes I wouldn’t imagine any accent other than what I’m used to from California. I wish I could speak with such clear diction.
If this zombie were in the Pit I might wonder if the question would even be posed in different circumstances.
Gee, if only I had said that her accent was very “ever-so-slight” in the OP. Oh wait, I did.
Well, this is GQ, so let me give a factual answer to your backhanded question. I am a student of accents, and a I encountered a newly prominent person with an accent I was not familiar with. Those are the circumstances.