Setup:
- OS X 10.9.5
- VLC 2.2.1 "installed" (present on local storage)
- System preferences -> Language and region:
Region set to some non-English region (Slovakia)
Preferred language set to English
Advanced -> Format language set to Slovak
- Some video (youtube or whatever) downloaded in JD2's download list
In this setup, VLC correctly uses English if:
- it's launched as an application
- it's launched by opening a video from Finder
- it's launched by opening a downloaded video from Firefox or Chrome
But when I open the video from JD2, VLC uses Slovak.
I suspect JD2 is dropping some environment variable when launching VLC.
Further info - Chromium actually used to do this too, but it stopped quite some time ago (several months, at least). I have no knowledge whether there was any bug reported, and/or who fixed it there.