Hello,
Changing the language on the admin panel may not give you immediate results. It's best to fully refresh EPESI before continuing.
Another possible reason for the problem is when you change your language in Control Panel, you no longer use "system default" value and changing that system default will make no effect on your user account.
For the solution: go to your control panel, Regional Settings and select English there. Then, refresh EPESI (F5) and it should be working.
Kind regards,
Arek