You record a video, we create copies in all desired languages. Almost all known languages are available.
Not only the subtitle is translated, but also the human language. This is exactly how you know it from TV documentaries.
This allows you to tap into additional markets. This is because complete video courses can also be localized for additional language markets.
Tip: Don't just think about the English language market, which is already well occupied. How about Spanish, a very widespread world language with little competition? Or Russian and Chinese?
You can find out what it looks like (subtitles) and how it sounds in the following voice samples:
English 
Deutsch 
Español 
Italiano 
Português do Brasil