Chatterbox doesn't have a physical description.  Well, that's not technically true.  He <i>does<i> have physical presence in the form of the AA-1 Verbobrain that contains his processors and programming and is plugged into the ship's main computer.  But, he is otherwise without form.

The droid makes himself known by talking through the ship's PA system or communications array, acting as the ship's unofficial ambassador and cruise director.

He is incredibly (annoyingly) upbeat and cheerful, always speaking in a peppy tone with a positive thing to say.  But lurking behind that chipper persona is a first-rate comm tech and slicer.  Thanks to numerous programming upgrades and general tinkering by Burress Veran, Chatterbox's programming--like his counterpart, Q7-P10--far exceeds its original mandate.