php multilanguage site

Hello,

Is there any tutorial for making a php multilanguage site? I have seen some pages using at end of url: ?lang=en

How they do it? Thanks

Since there are so many possibilities (organization and technologies to use for example) when building a multilingual site - here are a few things to read that I highly suggest.

http://www.joelonsoftware.com/articles/Unicode.html
http://www.phparch.com/issuedata/articles/article_179.pdf

Thanks very interesting.
But I don't know how make a site which I can change the language. The only I know is that I must create a file with all text of a language and the same for an other language. And then I include a file depending on languge each visitor select. How I do that? Is there any tutorial about this?

The simplest way to do it (and the least scalable) is to make the site in various languages and place each in it's own directory. Then depending upon the language the user chooses have them go through that directory.

So main index -> choose language - link it to the languages index page in the lang directory. Make sure you have links between the various languages.

Ex:
www.domain.com/index.html <- choose lang
www.domain.com/en/index.html <- english main page
www.domain.com/jp/index.html <- japanese main page

If you want something more advanced check out gettext, and PEAR's Internationalization classes, or the IntSmarty templates.