I have successfully created a web site with internationalization. I set the required constants in the /config/site.php file using the language code found in the URI and the navigation works. The problem happens when I post information from a custom block. The URI does not contain the language code and the site reverts to the default language.

What is the best method to determine the appropriate language to set in the site.php file in this case? Session variables are not available, the Concrete5 Config::save()/Config::get() methods are not available.

Should I append a language parameter to the block's action? Thank you for your help.