#1
I don't normally listen hip hop (I use to to listen to hip hop but moved to rock) and tend not to notice singing and don't usually notice a good singer but the performance by Bridget Kelly (Obviously she has to be good if she is standing in for AK) a stand in for Alicia keys on Jay Zs - Empire State of mind really left me amazed. What I think stood out was she was singing and It looked effortless and she doesn't sing completely clean... I think as well as theres something about her tone.

Just thought I would share it.....Here's the link

http://vodpod.com/watch/2466611-vid-jay-z-empire-state-of-mind-2009-mtv-emas-live-performance

Is it possible to reach her level of ability for normal people or is she just extremely talented? Also I think in this song she does better than Alicia Keys
#2
I think some of it is just how powerful that part of the song is meant to be. The Alicia bit is kind of a sarcastic answer to Jay-Z's stuff , so it really has to make it's point.
But yeah, I do think Bridget did a far better job than Alicia also.
I would assume that you cannot teach that kind of vocal power. I'm pretty sure you have to be born with that. If one was gifted with said power, perhaps you could refine it to what is demonstrated here. But otherwise , I'd say no .
The only truly consistent people are dead people.