Subtitles don't work if you have no sound

What I expected to happen was...:
Be able to use subtitles due to not having a working speaker, and no easy access to headphones for my computer.

What actually happened was...:
Subtitles only work if there is sound. This is fine to adjust in the settings, but if your computer is incapable of producing sound, like my computer (as no headphones or speaker) it will still not give me subtitles. As such, to be able to use subtitles I have to plug in extra headphones to even get them to show up. 

Steps to Reproduce:
1. Have no speaker or headphones connected to computer (aka output)

2. Put on subtitles.

3. No subtitles