Hexedited scripts file to restore the American soundbank.
Extract the Scripts.vfs file from the folder and replace Scripts.vfs in the game's folder.
This will effect the American NPCs, most notably in the Shefferd mission.
Thanks to Liz Shaw from the Haggard Games forums. (The official forums of the game's devs)
They made a post talking about cut content and they walked me through how to manually replace the scripts file. (I just uploaded a "fixed" version so you don't have to use tools to fix it yourself.)