If the game defaults to a non-English language on Steam:
Given the complexities and risks associated with unofficial patches, the official Steam language selection method is unequivocally the preferred and safest route. It is the method officially supported by the developer, Rebellion Developments, and will guarantee that your game functions correctly with all future updates and DLC. Sniper Elite 3 English Language Patch-- Download
Sniper Elite 3 English Language Patch Download: How to Change Your Game Language If the game defaults to a non-English language