Japanese
polite language, which is a bitch to learn and use. Don't let people
bullshit you into believing that it's some sort of genetic trait that Japanese automatically have and
gaijin can never hope to acquire. In fact, most Japanese (two thirds in a study I read) don't think they can use keigo properly, while some (very few) foreigners have mastered it.
Basically, keigo is divided into three subcategories:
- sonkeigo - shows respect of the speaker towards someone (usually the listener) when describing that person's actions.
- kenjougo - the speaker shows humility (towards the listener) in describing his or her own actions
- teineigo - shows general politeness (of the speaker) towards the listener, not specific to who or what is being talked about.
Several factors make keigo very difficult to use: For every statement you have to assess the relative hiearchical superiority or inferiority between yourself, the listener and the person you talk about, as well as any people belonging to your or their "group" of associates. For example, when talking to your parents about your college professor, you may use sonkeigo towards the professor (especially if he's listening) because he's above you, but not kenjougo because you don't have to show humility towards your parents (except in bizarrely
old fashioned families, perhaps). But when talking to the professor about your parents, you'd have to use sonkeigo towards him and kenjougo (
not teineigo) towards your parents because they belong to your own group and thus must be described humbly when talking to a superior. There can be contradictions: what if your father is actually the college president and thus superior to the professor?
Furthermore, keigo itself is rather complex. It requires you to learn and use completely new words for common things, including new verbs for common activities. For example taberu is the normal form of "to eat", but it's meshiagaru in sonkeigo, itadaku in kenjougo (this is where itadakimasu comes from) and tabemasu in teineigo.
Failure to, or wrong use of keigo is percieved as rude, strange or bizarre, depending on the situation. Fortunately, foreigners are generally not expected to use something that even native speakers have difficulties with.
Thanks to mowph for corrections.