Why does the chapter called "Words" in Nightjohn differ from the others in its narrative style?
"Words" is the only chapter in Nightjohn that has a chapter title. The other chapters are titled simply as chronological numbers, "ONE," "TWO" etc. Since both the titling and narrative style change in "Words," we have to conclude that the message embodied in this chapter is an important one and one that Gary Paulsen wants to make obvious and plain to the reader.
The other chapters are the chronological narrative of Sarny's life and experiences. The chronology is interrupted by flashbacks that tell her backstory, as in "ONE" in which Sarny, the first-person narrator, tells about "mammy" and about the overarching theme of her narrative, Nightjohn himself.
This is a story about Nightjohn. ... There's some to say I brought him with witchin', ... but it ain't so. I knew he was coming but it wasn't witchin', just listening. (Sarny, Nightjohn)
The narrative style of these other chapters is straightforward, clear, informative as is typical of autobiographical narratives. Sarny tells about her life, about seeing Nightjohn for the first time, about Nightjohn's experiences at their plantation (including his rough beginning and his walking out on shoes he made then covered in lard and pepper to throw off the dogs who would hunt his scent) and about her experiences with Nightjohn.
In "Word," Sarny is celebrating Nightjohn and what he accomplished, what he gave them and how he walked to come to them and help them.
To know things, for us to know things, is bad for them. We get to wanting and when we get to wanting it's bad for them. They thinks we want what they got .... That's why they don't want us reading. (Sarny)
In order to celebrate Nightjohn and his gift of reading and words, Sarny switches from an autobiographical narrative style and tone to a poetical narrative style and tone. "Words" represents an ode to Nightjohn and his gift. While Sarny may not compose her ode in Shakespearean or Wordsworthian poetic style, her narrative stylistic change has the feel, the rhythm, the poetical affect and the powerful imagery of a classical ode.
Late he come walking.
Late in the night when they in the white house are all asleep and we be asleep and nobody can know nothing., late when the moon is down and the stars are hiding in clouds, late when it isn't the day before and it don't seem like ever the new day will come--that late he come walking. ("Words")
The narrative style in "Words" changes, then, (1) to dramatize the paramount theme, which is the gift of reading and words, and (2) to present a prose-style ode to the one who brought the gift--walking to them to bring it--that might make their minds free, even though the giving of the gift garnered him severe punishment.