In The Poisonwood Bible, how does Kingsolver use diction and syntax to create a unique voice for each of the five female characters?

Kingsolver's use of diction and syntax to create unique
narrative voices in The Poisonwood Bible is one of the highlights
of her writing.  The novel shifts between the voices of Orleanna, Leah, Adah, Rachel,
and Ruth May, and each chapter is labeled with the character's name.  However, the
distinct voices speak for themselves and after the reader becomes acquainted with each
character, he/she recognizes the voice of the narrator.  Ruth May is the youngest of the
five, so Kingsolver manipulates grammar to make her voice sound more child-like.  For
example, when Ruth May describes the toys she was allowed to take to the Congo, she
says, "I only got to bring me two toys:  pipe cleaners, and a monkey-sock monkey.  The
monkey-sock monkey has done gone already."  The slight grammatical mistakes are ones
that a young child would likely make, yet are not bad enough to impede understanding. 
Similarly, Kingsolver uses highly sophisticated diction an syntax to develop Adah's
voice which is ironic because the most intelligent character in the novel chooses to
remain silent.  So, Kingsolver uses the traits of each female character to characterize
her narrative voice.