Language by GET parameter - TranslatePress

Using the Language by GET parameter Add-on you can encode language in the url as a GET parameter. Your website will use URLs such as this one:

This will replace the language directory system which uses the following URL format:

There is no need for extra configuration. You just have to activate it and that’s it.

The default GET parameter used is lang. This can be changed using a bit of coding:

Create an empty plugin like this: https://gist.github.com/sareiodata/76f701e01db6685829db

Add the following code to the end of it:

add_filter( 'trp_gp_lang_parameter', 'trp_gp_change_parameter_name' );
function trp_gp_change_parameter_name( $name ){
      return 'language';
}

Replace language with the GET parameter of your choice.
Install this plugin via FTP (copy it inside wp-content/plugins) or create a zip archive with it and install it via the WordPress plugin upload functionality