Problem Description
- You're using Plesk's phpMyAdmin, but it somehow got set to the wrong language.
- Attempting to change the language using the config.inc.php file found in the phpMyAdmin dir for Plesk fails because there is no config.inc.php there (only the sample file).
Problem Resolution
Please note: you must have shell access to your server to make these changes. If you are not the root user of the server, you will need to ask your web host to help.
Plesk stores the phpMyAdmin configuration file here: /usr/local/psa/admin/htdocs/domains/databases/phpMyAdmin/libraries/config.default.php
Edit that file, look for $cfg['Lang'] and set it to 'en' so the line looks like this:
$cfg['Lang'] = 'en';
Save the file and reload phpMyAdmin and you should find the language set back to English. You can, of course, replace 'en' with any other language code.