After the latest update in Duolingo the speaker does not work in Safari
I just noticed that my speaker stopped working, mid lesson, with Rockmelt (Chrome based browser). About 1/2 hour ago.
I fixed my Rockmelt problem! Messing with my settings didn't really do anything, nor did rebooting my browser or laptop. Try logging out and then log back into Duolingo. If your settings are where you want them when you log back in, this might work for you too.
How do you know when an update occurs? I have Safari and my speaker quit working today. I worked yesterday and my speaker works with other applications.