I thought “True Grit” was a gem, and that the girl absolutely stole the movie. What you heard as “stilted” speech, I saw as extremely iconic and different from other movies, and liked it.
I think only the highly educated spoke that way and the characters in the movie were not of that type. The girl was wonderful, but the sound in the theater must not have been good because even I had trouble making out what they said. Big disappointment.