Answer:
What is so fragile that saying its name breaks it?
You use it between your head and your toes, the more it works the thinner it grows.
If you have it, you want to share it. If you share it, you don't have it.
Only two backbones and thousands of ribs.
I grow where no flower grows, where no light touches the walls, up or down, that I don't care, was here before people were.
What covers its face with its hands, speaks no language, yet most known what it's saying?
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?