The cortico bulbar tract is a direct uni-synaptic tract. It is also referred to as the pyramidal tract, although the pyramidal is also cortico-spinal. The cortico bulbar tract takes neuromotor signals to cranial nerves. The cortico spinal takes neuromotor signals to spinal nerves. The cerebellum along with several structures is part of the extrapyramidal tract, a multi synaptic tract.
The cerebellum compares the intended performance of motor neurons with their actual performance. When a signal for motor movement is sent from the cortex to a cranial nerve, a copy of that signal detailing its strength, speed, and target is sent to the cerebellum milliseconds BEFORE the signal reaches the muscle. After the signal innervates the muscle, proprioceptive feedback about the movement from tendons, joints and muscles is provided to the cerebellum. Thus, the cerebellum can compare the output from the motor cortex with the input to the muscle, and act accordingly. An example I like to use is when I pick up a milk carton from the refrigerator and assumed it was full, my hand jerked up suddenly UNTIL feedback from the cerebellum corrected the problem and I used the correct amount of force to hold up the carton.