The tongue is very important when animating your character, helping to create good facial expressions which are fundamental when animating dialogues. Although subtle in essence, it makes a big difference when animating your character while it's saying things such as "hello".
Not only when speaking, but what if your character wants to have an ice cream?
004-Tongue.blendfrom this book's support files. You'll find our character's face rigged with shape keys, lattices, and a jaw controller as the result of previous recipes.
If you move the Jaw controller down, you'll see that there's a mesh called Otto_Tongue inside the character's mouth. It is parented to the D_Jaw bone, so it follows the jaw movement. ...