- Can you hear the other sites? Can't hear only Common Voice?
- Can't hear even if you delete your browser data?
- Do you have a browser or extension set to disable sound?
- Can't you hear when you plug or unplug a device (microphone, headphones, etc.)?
If you don't see the sound icon on the tab, it may mean that the sound output itself is not working.
- OS (Windows, Mac, Linux, etc.) settings
- Device settings
- Browser settings
I can't answer more than that because there are so many factors. I'm sorry.
If the sound itself isn't coming out, I don't think it's a bug in Common Voice.
If you're using Firefox, you could try relying on support.mozilla.org a.k.a. SUMO (you'll need a Firefox Account to post your question):
- What to do if Firefox won't play any sounds | Firefox Help
- Fix common audio and video issues | Firefox Help
I've searched for Discourse and they all seem to be clip issues:
- No sound audible (or extremely low volume) during validation of sentences
- Dutch language: no sound on sentences
- No sound in recordings while validating other recordings
You might try searching Google or other sources for symptoms. Ref: browser audio no sound - Google