Website in different language

No, you don’t need different template (we say: theme).
You may want to try the polyglot plugin:
https://fredfred.net/skriker/index.php/polyglot

thank you very much moshu… I’m going to try it!

You are welcome. Hope it will work for you.
(also, clicking on my name you can look for a post titled Multilingual blogging – there is a more detailed description of what I’ve found)

Hi moshu, I’m tring to use that plugin..
Now I have a language menu in the sidebar, and if I change language, system change the language of posts and of date, by I’m not able to change, for example, all the titles of the sidebar (pages, blogroll…)
I have put the file .po of fr, but the titles doesn’t change yet.. do you know what I have to do?

Not having a link I have no idea which theme is in use on your site. However, I can tell you even without seeng the site, that thems has to be translated (localized, if you wish) by their own – since 1.5.x.
What that means, even having the whole WP translated (using a .mo) file, will not translate the theme!

For the time being this is the best description about theme localization that I know of:
https://boren.nu/archives/2004/11/01/localizing-plugins-and-themes/
(Ryan is one of the WP developers)

If you wanna you can try to use my plugin: https://gh3.altervista.org/simple-multi-language-plugin/

SML project is closed.
I have started a brand new one: Babel ( https://gh3.ellequadro.net/my-works/babel/ )