If you’re cringing at the thought, you can at least take consolation in knowing that these captions won’t arrive in earnest for a while. The tool is reaching marketers over the course of the weeks ahead, and only in US English for now. You’ll be safe for a while, folks. As it stands, captions might have an upside (other than allowing the hearing impaired to access what’s going on, if they choose): they could reduce the temptation for advertisers to use more distracting custom text in a desperate bid to catch your eye.
Source: Facebook for Business