This is simple and stupid Android tool that resets the OS language to EN.
It's intended to help with the awful Marshmallow bug (https://code.google.com/p/android/issues/detail?id=191068) that occurs on the Nexus Player.
After installing the app, you need to run this command: (adb needed)
adb shell pm grant com.example.langfuck android.permission.CHANGE_CONFIGURATION