Good animation, I like the texturing of the face. A couple of thing to watch:
a. The lips move quite fast, you may want to adjust the timing.
b. I would slightly close the bottom eye lid (move up a bit) to a more relax position.
c. Take some pause and inhale (move the chest outward lightly) in between some group of words or swallow for a more realistic look.
d. Blink more often but don't over do it.
e. Move the eyes up or to one side from time to time like if your character was thinking of the next sentence.
f. Open the mouth a bit like the character is taking some breath in between group of words.
g. You may want to investigate "sticky lips" for added effect.
Overall, a good animation, look forward for your next test with mocap.
P.S. Watch this guy talking (turn the sound off) and see the nuance.
http://www.youtube.com/watch?v=uuBJF2QiCSE