Without any announcement whatsoever, Facebook has launched the ability to add closed captions to your videos. Closed captions will make your videos more accessible to people who are deaf or hard-of-hearing.

Link: http://www.3playmedia.com/how-it-works/how-to-guides/captions-subtitles-facebook-video/?utm_source=eNEWS.071615.MedEl&utm_campaign=eNews.071715&utm_medium=email