Fun With "The Grunt of Incomprehension"

Here in killer cowboy land, the natives signal incomprehension with a guttural grunt--"huh?"
Repeat it to yourself a few times.
"Huh?"
"Huh???"
"HUH????"
Dreadful, really....... but with what might one replace this aspirated exhalation of bewilderment?

May I suggest the renewed usage of the archaic and quaint "prithee"? It would offer endless hours of amusement a la Abbot and Costello:

First Speaker: (inaudible mumbling)
Second Speaker: Prithee?
First: Huh?
Second: Yes, essentially........
First: Huh?
Second: Exactly....
First:(shoots second)
Second: AAAArgh!
First: Huh?

and so on