If the cerebellum is not functioning properly than involuntary processes will get disturbed. It is responsible for maintaining body posture and equilibrium by controlling & coordinating muscular movements. But if it's not working properly then the balance of the body gets disturbed. We will not be able to walk properly. Thus the body parts which are responsible for our movement will not respond.

Explanation: Cerebellum is the part of Hind-brain. This portion of the brain is maintaining the voluntary actions of a body which are under the control of a person. Example: Picking up of a pen.