One of my chief pleasures in reading children's books is the authorial voice (or the book's storyteller voice), which tends to be different from adult books. I've examined a few favorite books to help nail down what it is.
Funny/Odd Character Names:In Roald Dahl's Charlie and the Chocolate Factory, the grandparents' names match: George and Georgina, Joe and Josephine. In Neil Gaiman's Coraline, we have Miss Spink and Miss Forcible. Sometimes the other characters have odd names but not the protagonist.
A Childlike Voice of AmazementThe voice may use "huge" or "very" (Neil Gaiman in Coraline) or otherwise verboten adverbs and simple words of aggrandizement (Dahl again):
"The house wasn't nearly large enough for so many people, and life was extremely uncomfortable for them all.... The bed was given to the four old grandparents because they were so old and tired. They were so tired, they never got out of it."* [emphases mine]
*The Absurd, Odd or Surreal Not Remarked uponNote there's one bed for four people, two married couples in one bed in which they stay all the time for being tired. I first noted this in L. Frank Baum's Ozma of Oz as a child. Why isn't the character or storyteller more amazed?:
" 'Over to those trees, to see if I can find some fruit or nuts,' answered Dorothy.
"She tramped across the sand, skirting the foot of one of the little rocky hills that stood near, and soon reached the edge of the forest.
"At first she was greatly disappointed, because the nearer trees were all punita, or cotton-wood or eucalyptus, and bore no fruit or nuts at all. But, bye and bye, when she was almost in despair, the little girl came upon two trees that promised to furnish her with plenty of food.
"One was quite full of square paper boxes, which grew in clusters on all the limbs, and upon the biggest and ripest boxes the word "Lunch" could be read, in neat raised letters. This tree seemed to bear all the year around, for there were lunch-box blossoms on some of the branches, and on others tiny little lunch-boxes that were as yet quite green, and evidently not fit to eat until they had grown bigger.
"The leaves of this tree were all paper napkins, and it presented a very pleasing appearance to the hungry little girl."
Stating the Obvious (or the Obvious from a Childlike Perspective)Sometime the voice tells us what we already know (Neil Gaiman in Coraline), which is part of the charm (is it because nothing should be taken for granted?):
"It was a very old house--it had an attic under the roof and a cellar under the ground."Here's a famous Lewis Carroll line that some may or may not take to be true, yet it has a certain ring of truth even if you don't agree:
" 'What is the use of a book,' thought Alice 'without pictures or conversations?' "***
I doubt this is any way complete, but it's what strikes me on a quick revisit of old favorites.