You have 6 major and hundreds of minor salivary glands.
They make saliva
(spit), which is important for oral hygiene and digestion. Your 6 main glands are the paired parotid (in cheeks), submandibular (under the jaw) and lingual (in the floor of the mouth). A "disorder" would encompass many problems like infection, blockage (salivary stones), inflammation
, tumors, etc.