even if there is the slightest glimmer of short-term memory,
some momentary awareness, there *is* consciousness, even if
minimal.
I've worked with extremely disabled kids - full time for a year
- in my early 20s.
Language, ability to perform tasks that indicate to the outside
world that "there is somebody in there", is not required, imo,
to determine consciousness.
Even brain scans are imperfect, for the very procedure for
measuring mental activity can be distressing and cause someone
receiving an input-overload from the environment, could shut
down out of fear and show nothing much on the instruments.