In Diné (Navajo) culture it is an expression used to acknowledge something in
disappointment and/or
apathy, or even in a comedic condescending
way.
It can be prolonged to “wahhh” depending on context and how the user decides to use.
Rez dude - “Hey did you hear your
uncle so-and-so picked up a
new ride?”
Rez chick - “No huh uh, what did he get?”
Rez dude - “don’t even know, it’s an old used
truck.”
Rez chick - “Wahhh”