Aside from Addie, all the Bundrens appear to have had very little schooling, do their monologues contradict or support this idea?

As you can see from the short excerpt below, Faulkner uses a local dialect, which is more pronounced in the younger children than the older children.

"The book is written in alternating short chapters from the points of view of all the different main characters. Vardomon, the slowest of the children, narrates in an incomprehensible stream of consciousness in local dialect. Darl, the second oldest, on the other hand, alternates inconsistently between dialect and sophisticated vocabulary with poetic narration."