This guide is simplest it's ever been — made in 2016, last updated in 2024,
having a ton of text finally simplified to 4 simple steps with the help of commentators
and collaborative work of Claude_Lib, Jillas, Skexer and Tvorozhnost.

If you struggle to follow the guide, message Tvorozhnost or Jillas for help.

In Steam, if you have Russian language set in the game's properties,

Select Simplified Chinese instead — this will download the necessary English audio files.

Find and backup these audio files:

\Watch_Dogs2\data_win64\installpackage_english.dat
\Watch_Dogs2\data_win64\installpackage_english.fat
\Watch_Dogs2\data_win64\patch_english.dat
\Watch_Dogs2\data_win64\patch_english.fat
\Watch_Dogs2\data_win64\patch2_english.dat
\Watch_Dogs2\data_win64\patch2_english.fat
\Watch_Dogs2\data_win64\sound_english.dat
\Watch_Dogs2\data_win64\sound_english.fat
\Watch_Dogs2\data_win64\worlds\san_francisco\san_francisco_english.dat
\Watch_Dogs2\data_win64\worlds\san_francisco\san_francisco_english.fat
\Watch_Dogs2\data_win64\worlds\san_francisco\san_francisco_sound_english.dat
\Watch_Dogs2\data_win64\worlds\san_francisco\san_francisco_sound_english.fat

Keep in mind that there are also subfolders, 12 files in total.

Move the files outside of the game's folder — otherwise, they will get deleted by Steam during the next steps.

Exit Steam -- and make sure to wait a few seconds. Find the following file:

/SteamLibrary/steamapps/appmanifest_447040

Open it with a notepad, scroll all the way down to see these lines:

"UserConfig"
{
"language" "schinese"
}
"MountedConfig"
{
"language" "schinese"
}

If you don't have the "language" lines, you can safely add them yourself. These lines should still stay in the document even if you reinstall the game.
Simply replace both "schinese" with "english", then save and close the document.
Make sure that in the game's properties the language tab is now empty:






Launch Steam.
Once you're logged in, Steam will have to update Watch_Dogs 2 and delete the English audio files. Put the 12 files that you've acquired during step 2 back into their respective folders in the game's directory.



If not, make sure appmanifest is still set to "english", the properties language tab is empty and that the _english files are still in the data_win64 and worlds/san_francisco folders. It's all that matters.

You can have both "_russian" and "_english" audio files in the game's folder, giving you the ability to switch between voiceover languages on the go, during the game.

Since the _russian files aren't originally shown in the game's directory, you'll have to download the Chinese version, then Russian back again -- the _russian files should appear alongside _english.

Depending on the language you've set in appmanifest_447040, the opposite language files will get deleted once. Hence, backup one of the groups of files to restore later.

If you did everything right, you should now be able to switch the voiceover languages in the game's settings menu from English to Russian and back.
The game may warn you that the language you've just set isn't yet installed... it'll keep doing that, just ignore it.
Switchable text language is possible.