July 2020 - last edited July 2020
If you play tapped out in Bluestacks you can get sound back by installing a new 64-bit OS instance through the multi instance manager, I've never had to do this before ive been playing tapped out on PC since 2013 via the default 32-bit bluestacks install but this works for now until they fix it proper.
July 2020
Same problem on my Samsung tablet and my Huawei p9. Sometimes I here sound for a few seconds and than it's gone. Been like this for a long time now.
August 2020
I too have lost sound in the game. I've double checked all the settings and even reinstalled the game w/o fixing issue. Very frustrating.
January 2022
The switch by the volume button was my issue. Some how it got switched to off.. weird.