I’ve always wondered why Jane brought a book intended for toddlers with her to the jungle. My headcanon is that her mother use to read this book to her when she was younger, which is why the character’s name is also Jane. Jane holds this book dear to her heart, because it’s a memory of her mother. And she brings it along with her when she travels away from home, so in a way, to have her mother with her always. She most likely does not show it to others, but the fact that she’s using it to teach Tarzan how to read just shows how close their bond is.
((This is a FANTASTIC headcanon, I love it XD