This is a Unity engine bug caused by trying to play games on Linux with a non-English locale. There is an easy work-around to the issue, however, which requires that you explicitly set the game's locale to "en_US:UTF-8".
To do this on Steam:
- Right-click Torment in your games Library
- Go to Properties -> Set launch options
- Add "LANG='en_US.UTF-8' %command%".