How can I have support for multiple languages at once?

It possible multiple languages, so for example you may have 2 languages at the same time and the user can choose the language by clicking on a flag,

The langauge can be changed on-the-fly by appending a `lang` parameter to the url.

For example, if you have English with the code EN and French with the code FN, simply append the lang parameter like this:

http://www.example.com/users/index.php?lang=EN – change to English
http://www.example.com/users/index.php?lang=FN – change to French

Please note that the lang parameter is case sensitive.