Sensei,San,Chan,Kun
 

i think it would be riku-san,

but i wouldn't really know

you need the language section

You should ask this in the Japanese Language Help Forum.

Jaydelart is right. I doubt if you will get good answers in General Discussion. People will be answering saying "I think...", "I heard that.." , etc.

Believe me, this question is much more complex than you have probably thought. There are many exceptions as well as general rules. Those who don't speak Japanese fluently or who have never attended school in Japan will not be able to answer this.

I will gladly give my answer in the Language section.

EDIT: Oh...here it is.

In general, teachers address boys by their last name and "-kun".

teachers usually call students by their last name and i think they'd use san. sempai is for any upperclassmen or anyone in a grader higher than your own basically. chan is more feminine or for children, like a cutesy way of calling someone i guess. ppl usually use this for close friends too. hope this helps. sorry if i'm incorrect

By teachers:

Boys: Last name+kun

Girls: Last name+san

In terms of how students refer to each other, it is all over the map.

hmm, depends on what age you are, what kind of teacher you have. my teachers called me -san, but i only got japanese in university level.

some of my japanese friends call me chan, but not that often. mostly they leave away everything.

I think ~kun ends in high school. However you can can hear bosses use it for their younger staff. Even to women, sometimes.

yeah, sometimes my bosses call me -kun, but i'm pretty young. it felt pretty nice the first time they used it.
you're living in japan right? how do you address your friends? i normally drop the -san , also to older friends. but even than it depends on my relationship with them, how old they are etc.

-kun are widely used among peers, as -san would be too formal and polite, not quite within the circle kind or a thing.
While -chan would be for close , familiar and affectionate friends.

When I was in the university in Japan many years ago, I have had friends calling me -chan, -kun, and -san. It all depended on how close they were to me.

I noticed friends who were close didn't use any endings... they only used their name (sometimes their last name). If they kind of knew them but didn't, they used san... My teachers always called me by rion-kun.

Chan I'm not so sure... My family called grandparents obaachan and ojiichan and my older brother and sister are oneechan and oniichan

I agree with you....as far as I know -chan is used for kids too and most for girls....

There are plenty of boys who are ~chan. Even in adult-hood.

I knew a Kin-chan who was a businessman at least twice my age.

There is no easy answer to this question.

hahaha... i learned something
 

hehehe.. i kinda understand a lil bit about using "san,Kun,chan"... ^^

thanks guys... ^^

There really is no straight answer, but there are safe answers.

In reality, people call others by a big range of things.

When I was in high school, here in Japan, there were people in the class who everyone called by their family name with -san, all the way to people who were called by some nickname. It really varies a lot depending on the person.

As a more recent example, my husband is called by an incredible range even within his company. There are bosses who call him with -chan, and people lower than him who use -kun, etc. The only thing I`ve NEVER heard is flat out 呼び捨て (nothing on the end)