In a few countries, there are special rules to adress people who are of a higher or lower status, and so it is in Korea.
People who are older, such as parents and grandparents, are adressed more formal, but also strangers of about the same or greater age, employers, teachers, customers and so on. If the other person is a younger stranger, a student, an employee, a child, … they are inferior. The suffix -nim (-님) is used to make a term honorific.
Here are a few examples of these honorifics:
– you call your own grandmother halmeoni (할머니), but someone elses grandmother is halmeonim (할머님).
– your father is abeoji (아버지) while your friend’s father is abeonim (아버님).
– if you’re a man, you call your older brother hyeong (형), and a friend’s older brother is then hyeongnim (형님). Your older sister is called noona (누나) and your friend’s older sister is nunim (누님).
– if you’re a women, you should call your older brother oppa (오빠) and your friend’s older brother will be orabeoni (오라버니). Your older sister is eonni (언니), there is no honorific for this one, so you call your friends older sister eonni too.
– when speaking to someone of about the same level as yourself, you add ssi (씨) to their full name or only their first name. Adding it to only their last name is considered rude, since it means you consider yourself of a higher status.
– Seonsaeng (선생) is used to address a teacher, it shows respect. It is derived from Chinese and literally means ‘mister’, ‘one born earlier’.
– Lastly, there is seonbae (선배) and hubae (후배). Seonbae is used to address seniors or more experienced people. For example, students call their senior students seonbae, junior athletes call their senior ones seonbae in a sports club, more experienced or senior colleagues in business are called seonbae too. It can be added to the name or used by itself. As for hubae, this is only used to refer to juniors, not to address them, so as a third-party.