To change the language in Silent Hunter 5: Battle of the Atlantic
Change it to Language=en or Language=English depending on what the current string looks like. Save and exit. Method 4: Steam Properties (For Digital Versions)
TWoS is designed for English and German primarily. Other languages (French, Italian) may have partial support.
Find the section:
Changing languages after installing major mods like TWoS can break the interface. It is best to set the base game's language before applying any mods.
Right-click the Language.txt file, go to Properties, and make sure "Read-only" is unchecked before you try to edit it.