[HarryHirsch]

There is a simpler device, a glass plate with the alphabet held between the patient and the other person. Humans are extraordinary good at following someone's glance, and this is how a quadriplegic patient can spell out words. Franz Rosenzweig used such a thing in his last years.

It's surprising that no one has used a camera plus ML whizzo stuff including predictive text to speed up the process.