I believe it requires a PC and Cyberlink software. It can also be operated by slight eye movement. The new version that just came out this month also operates as an EMG switch detecting slight muscle activity throughout the body. It is a stand alone switch. Many people have used the beep that the unit makes when the switch is activated for basic communication.
Silence means No.
He also writes poetry. It's a very moving story. The website has mainly short clips from the stories. They take more practice and patience because they get so weak. When our friend John, a PALS who lived with us the last few years of his life, first lost the ability to move even his eyes, we had an EMG built for him.