There were a lot of unnerving sounds coming out of that guy (general consensus: Billy?), aside from his repetitions. The one that seemed to overwhelm the others, to me, was the chattering of a money/monkeys. Which reminded me of the room above the convenience store in FWWM.
He's repeating what he hears. Naido is talking in distorted monkey chatter, possibly reference to the monkey in FWWM who whispers "Judy".
Monkey see, monkey do.
The repeating everything Chad says is, of course, reminiscent of our man Dougie.
Did anyone also think the window-washer at the hotel in Buckhorn (the one whose work hurt Gordon's ears) also sounded and moved like a stereotypical monkey?
I've been wondering if the 'monkey sounds' were created by slowing down the audio. Even if so, it's probably unlikely that they'd be decipherable as language at another speed...
The Drunk repeats words, but he does not repeat the sounds Naido makes. He seems to be responding to her. Definitely not repetition.
He pretty much just repeated what he heard. Much like like or dear friend Dougie Coop.
This is the second time in 25 (or 26-ish) years men (?) in the Twin Peaks jail deliberately imitated animal noises.