Later, when attempting to learn Spanish in Bolivia, Etta wants Butch to speak Spanish to her to show how far he's come. What does he do? Take out a little paper with Spanish words and reads it out.
It comes back to bite him during their first attempts at robbing a bank, with Butch speaking Spanish very hesitantly and repeating the same sentences.
Butch: "Todos ustedes... arrimense a la pared." note "All of you, back against the wall." Sundance: ... They're against the wall already! Butch: "Donde es..." oh, if you're so damn smart, you read it!
Early on in the film, after the first Flyer robbery, the local town's marshal tries to gather a posse to catch the Hole in the Wall Gang. He starts off very soft-spoken and reasonable ("How many of you want me to supply you with horses?") to trying to guilt-trip the posse ("If you want your children to know I fought them by myself, that's fine.") to just resorting to screaming aloud at them ("That is why I'm your marshal, and that is why you and you and you are riding with me!"), with only the last of these eliciting a response. Said response being a bike salesman coming up to the stage hawking his wares.
Even better, right before Sundance goes off to visit Etta, the crowd is seen in the background, crowding around the bike and ignoring the marshal.