Thanks for the report. That happens occasionally but I'm afraid we can do nought about it. Usually, it's because the provider is unable to play the file, which means it'll probably work a few minutes later, but there's no guarantee. For instance, it's working right now for me, which makes it more likely that it was just a temporary glitch.
There's an exception, though: there are a few sentences where the audio is so bad that we turned it off. In those cases, you won't be shown a microphone icon, so you'll know whether the sound ought to work or not.
Thank you! I appreciate the answer. I'[m working very diligently at becoming fluent in several languages, so perhaps I take this too seriously. I'm a retired electreo-mechanical engineer, so I expect things to work, or I will fix them (haha). That used to be my job. I do understand the problem. Thanks again!
Yes, I program statistical modelling on website backends for a living, so I know what you mean - and it's extra frustrating when I have a pretty clear grasp on why it doesn't work. :) But just so you know, courses are created and maintained by volunteers who do not have any kind of code or infrastructure access, so the answer to anything such is usually - and unfortunately - "I'm sorry, we can't affect that."