Just a heads up.
This code works on Renpy versions up to 8.3.7
But it wouldn't activate on the same game project on the 8.4.1 version unless I set the callback=speaker("") (which would make all of the characters talk).
I'm a total zero when it comes to coding so I hope this comment isn't too much of a bother. I super duper really love this code and have used it for multiple projects, some of which aren't even games. It's incredibly convenient and has saved me hours of work.

