Japanese name suffices

See discussion for Reichu's note to editors.

Category 1

Notes: You NEVER refer to somebody as other than "-san" unless you KNOW you're in a close relationship with them. The same applies to refer to somebody by their first name.

Lack of suffix as well as calling a person by their first name indicates a close relationship between two people (Such as two people living together).

-san (さん)

Equivalent to Mr or Ms/Mrs in Japanese. Used for people you don't know real well or people in higher authority than you.

-kun (君)

Denotes more of a close relationship. Longtime friends may refer to each other as this. Usually used for boys, but can be used for girls as well. (Unsure if this would imply the female being masculine or not though)

-chan (ちゃん)

Denotes more of a close relationship. Longtime friends may refer to each other as this. Usually used for girls, but can be used for boys as well, though it could make them seem effeminate (though such things don't necessarily have the weak connotation it does in English).

-sama (様)

Equivalent of Lord or Lady. Denotes people in very high authority, such as royalty and the like.

Category 2

-sensei (先生)

Can be used for teachers, doctors, etc.

-sen/mpai (先輩)

"Senior", as opposed to kouhai, which means "Junior".

Category 3: Professional Titles

In alphabetical order. (Missing a few...)

-fukushirei (副指令)

"Sub/Vice/Deputy/Etc.-Commander".

-hakase (博士)

"Doctor" (Ph.D.).

-ichii (一尉)

"Major".

-kyouju (教授)

"Professor".

-sansa (三佐)

"Captain".

-shirei (司令)

"Commander".

References

If you put anything from Wikipedia here, you are already dead.