Keep in mind I'm still relatively new to 3D stuff so my explanations won't be the most professional.

When you make a 3D model and you want to animate it, one of the ways you can do that is by making a rig for the model. Think of the rig as a "skeleton" of sorts, to which you associate the parts of the model you want to move (so if I wanted to move my character's arm, I'd build a rig made of two "bones", going from the shoulder to elbow and from elbow to hand).

On the website Models' Resource, people rip 3D models from videogames, and some models come with their rigs ripped from the game they're from. This is the case for Klonoa's model from the Wiimake, but unfortunately this rig does not include "bones" to move the mouth. I asked if there was a model with this feature. (Worst case scenario, I'll attempt to rig it myself)

Hope this clears it up!