What is the best way to start a new language section

[tansu]

Hi mates.
I have a six years old forum and decided to start an English section in the forums.
mysite.com is the old one
mysite.com/en is the new one
I want to share users
I do not want to share other stuff. Even I do not have to share user profile information like post count, reps etc. Passwords and user names are quite alright for me.

What is the painless way to do that?

I tried split forums hack, but the core language stays the same and most of them image buttons in my language.

Is there anyone able to do this and give me a little hint.

regards