In fact Korean has not less than six politeness levels, that are realized inter alia in the pronoun system amd in verbal inflections. Sohn (1999) defines the politeness levels as follows (some details are left out):
â€¢ The plain level, which is the lowest level, is used, in general, by any speaker to any child, to oneâ€™s own younger sibling, child, or grandchild regardless of age, and to oneâ€™s daughter-in-law, and also between intimate adult friends whose friendship began in childhood.
â€¢ The intimate level is between close friends whose friendship began in childhood or adolescence.
â€¢ The familiar level is slightly more formal than the intimate level, typically used by a male adult to an adolescent such as a high school or college student or to oneâ€™s son-in-law, or between two close adult friends whose friendship began in adolescence.
â€¢ The blunt level, which is gradually disappearing from daily usage probably due to its authoritative connotations, is sometimes used by a boss to his subordinates or by an old generation husband to wife.
â€¢ The polite level is the most popular level towards an adult, and is used by both males and females in daily conversations. It is less formal than the derential level.
â€¢ The deferential level is used in formal situations such as news reports and public lectures.
(Linguistics for Students of Asian and African Languages ch. 7, p. 13)
I think this is very interesting. I like the idea that there are levels of politeness. It would be very interesting. Lee and Miller, science fiction authors who I like their work, have a world where politeness is like this. Trying to bring it into English is a bit of a challenge, of course.