How to change startup language on Windows 7 Professional

Hello!

I've recenly installed SSD drive on my Dell Latitude e6420. I've used Dell OS Recovery Tool to install new operating system on that drive (Windows 7 Proffesional x64 ). Everything works fine but the startup language ("starting windows" screen, options after hard reboot etc.) is set to English and display language ( all the GUI ) is in Polish. 

How do I change the startup language to Polish?

It is simply annoying to see the startup in English and all other stuff in Polish. I'm running on A25 BIOS revision, and the system boots from UEFI. 

I've changed language in Windows Control Panel and set the Polish language as default everywhere. I've also checked the registry on HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\MUI\UILanguages and there is only pl-PL key. I've even tried bcdedit \set command for current and default and everywhere the language is set to Polish (pl-PL).

but the startup is still in english... 

Is there any way to change it? On my previous system everything worked fine. Does it has something to do with the UEFI boot? Pls help.