Players generally use one of three primary methods to ensure their game runs in English: Steam Digital Management : For those with the Steam version
This is the only recommended method for most users. Do not download random .DLL files from file-sharing websites. Instead, use Steam's console to force the download of English assets.
If you're considering downloading the English language pack for Dawn of War 2, it's likely a good idea, especially if you're more comfortable playing in English or if you're having trouble understanding the game's content in another language.