Inside the main game folder, go to: \SoundData\PC\
Verify that you haven't muted "Voice Volume" in the in-game options menu. A Quick Warning Inside the main game folder, go to: \SoundData\PC\
To restore English voice acting, you must manually place the sounds_eng.pck file into the correct game directory. Inside the main game folder
In the Assassin's Creed series, audio is stored in .pck (Wwise Package) files. The sounds_eng.pck file contains all the for the game. Without it, you might see characters moving their mouths in cutscenes with no sound coming out. How to Fix Missing Audio Inside the main game folder, go to: \SoundData\PC\