|Daniel Ridgeway Knight's painting of "A Discussion Between Two Young Ladies"|
As with several languages today, there existed a formal and informal way of speaking in medieval England. The form used depended on the person being addressed, those present, and the speaker’s intent.
FORMAL, using “you” (Example: You are a true friend) was used with parents, an employer, any noble person, horses (they were considered noble animals) and anyone one was flattering.
INFORMAL, such as “thee, thy, thou, thine” (Example: Thou art a true friend) was used with spouses, close friends, children, servants, non-horse animals, inanimate objects, God (He was, and is, considered an intimate friend) and any person one was insulting.
A basic rule was never use the informal with anyone you would address as “sir,” such as a knight, unless given permission to do so.
“Ye” was used when addressing more than one person, being the plural of formal and informal (Example: Ye are true friends).