There are two steps to make sure that mutli-language module is actively working on your store.

Step 1: Enabling the module from theme settings

Please go to ocCommerce → Settings admin panel and click on the first tab General Settings. Now in the second option where it says Enable Multi-Language Module please make sure that is Enabled then save changes in your dashboard.

Step 2: Editing wp-config.php file

After enabling the multi-language module, now you need to edit your wp-config.php file to make sure that your store will change the language dynamically based on customer’s choice.

The wp-config.php is located in your WordPress installation/root directory.

Please open your wp-config.php file and add the following bits of code somewhere before the end of the file:

if ( isset( $_GET['lang'] ) ) {
   setcookie('WPLANG', $_GET['lang'], time()+3600, '/');
   define('WPLANG', $_GET['lang']);
} else {
   if(isset($_COOKIE['WPLANG'])) {
      define ('WPLANG', $_COOKIE['WPLANG']);
      $_GET['lang'] = $_COOKIE['WPLANG'];
   } else {
      define ('WPLANG', '');
   }
}

Save the file and close. Your multi-language module is now active.