Quote 1
"Hold! Who comes here into Sherwood Forest without my pass?"
"Guy of Guisborne wants no man's pass. Who art thou that -- that --"
"Dares to hold such language," said Tom, prompting -- for they talked "by the book," from memory. (8.17-19)
Here we see that Tom and Joe Harper are actually able to change their manner of speaking to suit their role-playing; they, like Twain, understand what a difference "voice" can make. (It should also be noticed that Tom has no trouble remembering lines from Robin Hood, but he can't even memorize the smallest bit of the Sermon on the Mount for Sunday school.)
Quote 2
"Yes, and they take loaves of bread and put quicksilver in 'em and set 'em afloat, and wherever there's anybody that's drownded, they'll float right there and stop."
"Yes, I've heard about that," said Joe. "I wonder what makes the bread do that."
"Oh, it ain't the bread, so much," said Tom; "I reckon it's mostly what they say over it before they start it out." (14.16-8)
However silly their superstitions may be, the boys do understand the sometimes magical power of words.