You could easily design a system that picked up what is known as "sub-vocalization." It's similar to how those nifty ear-pieces that the government uses (note that there is no audio reciever that captures audible sound). Sub-vocalization is essentially speaking without making a sound. You move your mouth as if speaking silently to yourself and while no audible noise is formed an earpiece can pick up the vibrations through your jaw and convert it to an audio signal just as easily as any other system. These things are really cool actually. Just wish my camera had one now

. Maybe they could also equip it with one of those retinal-scanning display systems now in use for fighter pilots... (ie it scans a beam across your eye giving you a "heads up display" that you can see through and follows your eye/head movements)!