So, right now this on that.
Also note the post from the CX forum where they also posting messages on their IFE. I would think AC could do this - at least on the new systems on the 788/9s and 777s.
As I posted from onboard one of my AC 15s, pre-departure, crew made the announcement in 3 languages. Still not sure anyone has one or brings it aboard or heeds the instructions.
CX link
http://www.flyertalk.com/forum/27317779-post13.html
.