So I picked up my phone this morning and started typing...and there was no sound. I quickly checked its settings (I use Hacker's Keyboard) and everything was set as usual. I cleared its cache and data, then force stopped and restarted it. No sound.
I checked System Settings and verified that I do have sound--just not keyclick sound.
It doesn't matter which keyboard I use (I tried Gboard, too, as well as the phone keypad); vibrate -does- work but keyclick does -not- work, and it always has.
I rebooted my phone. Still no sound.
On my phone, I RELY on that sound, because it's so hard to see the itsy-bitsy keys, I like hearing a click for each key press.
I'm fresh out of ideas. Note that it's NOT specific to Hacker's Keyboard--it's ANY keyboard, in ANY app that you can type in. It's NOT a sound problem, like a system problem with sound going out, because everything else works (like alerts and music and ringtones).
Moto Z2 Force Edition, Oreo 8.0.0, not rooted.
HELP?!!!
I checked System Settings and verified that I do have sound--just not keyclick sound.
It doesn't matter which keyboard I use (I tried Gboard, too, as well as the phone keypad); vibrate -does- work but keyclick does -not- work, and it always has.
I rebooted my phone. Still no sound.
On my phone, I RELY on that sound, because it's so hard to see the itsy-bitsy keys, I like hearing a click for each key press.
I'm fresh out of ideas. Note that it's NOT specific to Hacker's Keyboard--it's ANY keyboard, in ANY app that you can type in. It's NOT a sound problem, like a system problem with sound going out, because everything else works (like alerts and music and ringtones).
Moto Z2 Force Edition, Oreo 8.0.0, not rooted.
HELP?!!!
That's the bad news.
I don't know how/why, though. 
It literally just started working as unceremoniously as it had stopped. So while I'm marking this thread solved, I can't post anything helpful for someone else who may have the same problem.