Nicholas J. Michalak said:
Grabbed this quote from Wookiepedia:
"You think Lobot's mute, but he's just too busy talking to the central computer to bother speaking to us 'organics'."
--Lando Calrissian
Yeah, in some of the EU books, he talks. I prefer to think he's mute. (or just chooses not to speak, like Buckethead) Much cooler. :p