Honorifics
Guide to honorifics
In Japanese an important cultural aspect is to have honorifics to show how people relate to each other.
No honorific
Used between people who are close to each other. If the honorific is dropped between people who aren't close, it's kind of insulting.
-san
Basic honorific, used to show general respect.
-chan
Normally an honorific used to show endearment, see Date from OOO. Can be kind of condescending though. Typically used with girls.
-kun
Normally used to address boys or co-workers in a lower position than the speaker (This applies to women in this case, like Satonaka-kun used by the president in OOO)
-sama
Used to show respect to someone higher than the speaker.
-shi
I don't see it used as often, but it's used for formal speech and for people that are generally unfamiliar to the speaker. Tends to be used in formal situations like in newspaper articles or news broadcasts.
-sempai/senpai
Sempai is used for people who are the senior or higher level than the speaker. Like in school or profession.
Kouhai
Kouhai is the opposite relation, used to refer to people in the lower level.
-dono/tono
Literally means "lord". Not really used nowadays, but it's used to show a lot of respect to a person.
-tachi
Not really an honorific, but kind of used to show the social structure of a group. Literally means "name of person and others". Since Japanese words tend to be used for both singular and plural, a -tachi can be used to show there's more than one. Like samurai-tachi would show there's a group of samurai. Or Alata-tachi would show that Alata is kind of the main guy in this group. Stuff like that.
External Links
You can also read it on the wiki which goes into much more detail than is presented here. I highly recommend it if you enjoy the Japanese cultural bits that are presented in #TV-Nihon's subs.