Windows 8 Acer Aspire P3

Open Control Panel and find the Language panel:

Gh7ZaVO.png


Click Add a Language, and the pick English (the list is sorted alphabetically)

qehkcsa.png


Then click Options next to English, and tell it to download and install the Language Pack.

DjdBoJP.png


You will probably need a reboot after the install is complete. If this doesn't solve it, I think you will probably need to get your hands on a natively English version of Windows 8 and reinstall the OS.