How do they make the Tweenie's mouths and eyes move?

Question

So the people inside the Tweenie costumes use their arms, hands and legs, what do they use to make the mouths speak in time with what they are saying?

Also, how do they make the eyes blink?

I'd love to know, since I can understand the rest of the movements, but these baffle me! Please only answer if you know!

Answer 1

I'd guess anamatronics - small motors within the mask that move the face parts.

Answer 2

by magic