Me too! I'm learning Italian and for the past couple of weeks the accompanying voice keeps coming and going.
I have a problem with a dodgy flash player installation and sometimes have to press control+space to get the sound to play. Does that help you?
I don't have dodgy flash player and I've actually tried to hit command buttons for a repeat and neither fast or slow repeat work.
I've done some troubleshooting, I can hear speech and sound fine in internet explorer but nit on chrome
I've only used Firefox up till now. Will try with Internet Explorer and see what happens!
I have problem like you. Please guide me if you have addressed this issue.