Kidliterate
I sell children's books for a living, and read almost nothing but. The first does not necessarily cause the second, as books for children and teens are better than anything in the world.
My Mouth is a Volcano by Julia Cook
My 7 year old daughter really struggles with what to say and when to say it. We are currently seeking a diagnosis we are fairly certain will turn out to be a combo of ADHD and OCD, and in the meantime are reading books and using roleplaying and activity books at home to augment the doctors' treatment. This book is FANTASTIC. Being able to give words to what happens inside her brain is so helpful, and having the description of her mouth being a volcano that rumbles and then the words just jiggle and erupt from her mouth has made some of our discussions a LOT easier. Highly recommended!