WILHELM SCREAM: Heard from off-screen after Roger pushes away his unneeded cart, in the segment "The Good Stuff!"
The young Ewok repeatedly says "Jeerota" which is Ewokese for "Friend" and "Yub Nub", which means "Freedom".
Excerpts from the pages of "From Trenches to Wrenches: The Roger Story", now titled "The Adventures of R0-GR", can be found as a fold-out in the 2018 reference book "Star Wars: Droidography", written by Mark Sumerak (but also credited to Ro-GR).