There are times I think he's using words that aren't his normal vocabulary. To me, it's a combination of him not seeming smart enough to know those words and their proper usage, going historically, added to the feeling that what ever he's trying to explain could be done more effectively using simpler terms.
If so, that would mean he's being fed things he doesn't understand anyway, thus he can't mark time or ad lib convincingly because he doesn't really know what he's talking about.
More telling, since I agree with you that he's being told what to say through some type of device, is that choice, as poor as it sounds and appears, must be the better alternative.