I thought of a dialogue peeve that I haven't seen in awhile.
Be they Native Americans or Indians or whatever you want to call them, I'd be willing to bet cash money that they didn't all speak in formal, stilted and sweeping statements when talking amongst themselves. I don't mind it too much in a lot of western movies, though there you too often run into the other end of the spectrum, with "Me Red Wolf, me heap big fighter" or whatever. But if an Indian character in a western speaks slowly and portentously it's often because it's a dramatic scene, and anyway it's not his first language. No big deal. And even if it is a big deal, it's pretty far down on the list of things most westerns get wrong.
But in a story where it's two Indians talking to each other? I'm no anthropologist or linguist, but I'm betting they wouldn't talk like that. I read a book where a guy is accidentally sent back in time 2000 or so years and is hiding from some Indians. They spot him, of course, and have a conversation about what to do and it's all
"Halt, my friend. Do you see that man behind the tree?"
"Yes, I see him. We should report this to the chief. He will wish to be notified, and it is his right as our leader to decide what to do."
"We are in agreement. The chief must know. Come!"
Or whatever. I'm guessing the conversation really could've been translated as something like
"Say, Bob, you see that guy behind the tree over there?"
"Yeah, I see him. Does he actually think he's hiding? What an idiot. We should probably tell the boss."
"Yeah, good idea. Let's go."