How to translate /en/file.php to file.php?lang=en in htaccess Apache

I'm writing multilingual website. I have several files on server like:

/index.php
/files.php
/funny.php

And would like to add language support by placing language code into URL like this:

http://mywebsite/en/index.php

would redirect to:

http://mywebsite/index.php?lang=en

And

http://mywebsite/en/files.php

would redirect to:

http://mywebsite/files.php?lang=en

I would like to put more languages for example:

http://mywebsite/ch-ZH/index.php

And I would like this to work only for files with php and php5 extension. Rest of files should be the same as they are.

So for example when i will go to address

http://mywebsite/ch-ZH/index.php

I would like my PHP to recognize that current path is

http://mywebsite

and NOT

http://mywebsite/ch-ZH

It's necessary for me because in my PHP code I relate on current path and would like them to work as they are working now.

Could you please write how to prepare htaccess file on Apache to meet this criteria?

From stackoverflow

• Something like this should do the trick,

  RewriteEngine on
  RewriteRule ^(.[^/]+)/(.*).php([5])?$ $2.php$3?lang=$1 [L]
  

  This will only match .php and .php5 files, so the rest of your files will be unaffected.

• Try this:

  RewriteEngine on
  RewriteRule ^([a-z]{2}(-[A-Z]{2})?)/(.*) $3?lang=$1 [L,QSA]
  

  And for the current path problem, you have to know how relative URIs are resolved: Relative URIs are resolved by the client from a base URI that is the URI (not filesystem path!) of the current resource if not declared otherwise.

  So if a document has the URI /en/foo/bar and the relative path ./baz in it, the client resolves this to /en/foo/baz (as obviously the client doesn’t know about the actual filesystem path).
  For having ./baz resolved to /baz, you have to change the base URI which can be done with the HTML element BASE.

• If you don't want to use ModRewrite, you can put symbolic links in the web folder (ln -s . en) and check the URL in PHP.