Final answer:
The nucleus ambiguus supplies motor innervation to the pharynx, larynx, and upper esophagus in controlling facial expressions, mastication, swallowing, and speech.
Step-by-step explanation:
The nucleus ambiguus supplies motor innervation to all of the above structures - the pharynx, larynx, and upper esophagus. It controls facial expressions, mastication, swallowing, and speech.
The muscles of the anterior neck, including those of the larynx, assist in deglutition (swallowing) and speech by controlling the positions of the larynx and the hyoid bone.