Apraxia occurs possibly more frequently with older people, as a result of a stroke or other neurological impairment. You'd think more communication devices would be used in those situations, but I'm not getting the feeling that they are. Wouldn't losing the ability to speak be even worse than not being able to speak in the first place?
Roger Ebert, the film critic, lost the ability to speak due to his surgeries. He says, "I would like a computer to provide me with my own voice." You'd think that would be possible these days.
Actually, part of what I enjoyed about this article is the sense of frustration he expresses. How much he misses being able to take part in conversations. A talker wouldn't help with that much, since they are labor-intensive. But many people can type faster than they can hand-write, so the lag would be smaller.
ASHA (American Speech-Language-Hearing Association) has a fascinating article about how augmentative communication can support kids facing the end of life, as they lose more of their ability to speak: Last Words, Last Connections.
On a brighter note, here's an interesting Reading Rockets article about including assistive technologies in your child's IEP.