Okay, first let me say this: please be sure you don't have a medical condition. Apnea can be related to heart problems, such as MVP. And yes, I
know the medical profession in general can be considered as 'quacks' with its own agenda, but that shouldn't stop one from seeking a rational
medical explanation.
Now, to confirm: I have also experienced the perception of 'many muttering voices', but not on awakening, as you describe, but rather immediately
before falling asleep, 'catching myself' and waking up before drifting off.
Also, I've had sleep paralysis experiences such as you describe -- waking up in cold sweats, and occasionally not actually waking up in body, but
only in mind. Quite disturbing really -- I realized I was dreaming, and tried to decide to wake up. Then, I experienced a dream-state 'shift', as
though waking up, but I still couldn't move my body or eyes. This
repeated several times -- quite horrifying When I finally woke up, my body
still felt tingly all over.
I know the body, when entering into sleep, 'disables' the connection between
perception of motor control and sensation, and the mental
activation thereof. This is, of course, what makes dreams involving physical activity possible. The subjective sensation of this, when it's not
synchronized correctly, is quite odd.
I haven't, myself, experienced the combined 'muttering voices' (which I've really only noticed very rarely, and I consider could be explained by
the same mechanisms as described for physical motion, applied to auditory perception) with sleep paralysis. But I imagine the combination would be
quite rattling.
Of course, to take an ATS slant -- if you're going to abduct or experiment on someone, cloaking the experience as 'sleep paralysis' or otherwise
explainable side-effects of natural phenomena would be an appropriate 'cover'.
So, no direct objective evidence here to back up your speculation, but hopefully you don't feel alone in your experiences...