What is the author's style in Dicey's Song by Cynthia Voigt?

The novel is written for young readers. For this reason, the novel's language is simpler than the language of a book written for adults might be. However, this book was written for children who should have a strong vocabulary and therefore contains some words that younger children might not understand. However, there are no foreign phrases of slang in this novel that a reader might not comprehend.