Amelie has figured out how to work the bouncy chair. In the video, she's bouncing herself back and forth and it almost looks like she's about to bounce herself out of the chair (she's not!). She also makes some pretty funny noises sometimes, and it usually sounds like she's vaguely offended about something. Mostly, though, she's just getting happy and worked up about all of the fun bouncing going on.
In this video, you can still see her bouncing. (I promise she's not going to fall out of her chair, really.) You can also hear her jabbering away, making an even greater variety of sounds. Make sure to turn the volume on your computer all the way up for the full range of sound effects.