I agree - for someone in his mental state, repeating words while simultaneously listening to the next ones will be nearly impossible to sustain for more than a few seconds. Probably even more disorienting than trying to talk while hearing a strong echo of your own voice. Like simultaneous translation - takes many months of practice to become good at that.
You are right.
It will certainly be an interesting phenomenon to witness.
Popcorn or peanuts? Beer or wine?