Roni Natov seems to cover this as she can in her article Child Power in Louise Erdrich's Fiction for Children. She very fittingly points out that children can understand more than we give them credit for, saying, "Children are aware of much that goes on outside their ability to articulate and evaluate complex problems". Natov also points out that in Little House, Laura does ask the hard questions about the territory they live in (if it's Native American land, if the government will make the Native Americans move, etc). However, Ingalls was an infant at the time this actually happen, meaning when she "rewrote" her past, she added these adult questions. Erdrich's situation in writing isn't much different, but she makes a much different decision in how she portrays a childhood knowledge of the world, the "child's power" as Roni points it out to be.
Erdrich shows how children do comprehend: not through the same words adults would, but by instinct and feeling. Omakayas, our main character, doesn't necessarily know what adults are talking about or what really is happening, but she does know when it's important or not. Once she notes it's importance, she holds onto it and finds herself referring back to it. While both are children's actions, this one seems much more childlike than Ingalls's version of herself in her series of books.
It is difficult, understandably so, to write from a child's perspective. It seems especially hard to do so while telling a historical tale that gives all the information of the time. It's much easier when one is writing from a child's perspective for adults, like John Connelly seems to do on a regular basis, or when one writes purely for children, like most children's books.
For those interested in writing from a child's perspective, here are a few links to help:
"Furthermore even if the writer does a very, very fine job of imitating a child, there will almost inevitably come a point where something rings false; a word or a phrase or a thought will be wrong or very difficult to attribute to a child. "
Child Narrator's in Adult Fiction
Take note of the suggestions of where to pull the ideas and look at the long list of recommended reading (which even includes the child narrator's age). The format is a bit messy, but worth the long read.
How to View the World from your Child's Perspective
Not necessarily a traditional writing tips article, but think about it: if you can learn how to see through a child's eye than that's about as helpful as any writing tip when it comes to writing from a child's perspective.