As mentioned, Johnny in the last phone conversation in the van is not talking to the person he thinks he is. The film reveals Takahashi at his desk, using his hand as if he were a sock puppeteer—but there is no puppet. His desk is emitting a grid of green light to track the movement of his hand and arm.
The Make It So chapter on gestural interfaces suggests Takahashi is using his hand to control the mouth movements of the avatar. I’d clarify this a bit. Lip synching by human animators is difficult even when not done in real time, and while it might be possible to control the upper lip with four fingers, one thumb is not enough to provide realistic motion of the lower lip. Continue reading