Outside of some stage actors and drill sergeants, there are probably few people who can project their voices well enough that a vocal warning is useful.

You're either traveling slow enough that it's not necessary (and why yell at people if you have to?), or are too far away for someone to understand and get a bearing on who isn't already looking at you.

A bell is still rude in a shared space but used correctly, a decent one can at least be effective.

> A bell is still rude in a shared space

I just don't think that is even a little bit true, or at least it's something that is very culturally specific and thus not generally applicable.

I have a friendly sounding bell I use from an appropriate distance (and I can modulate the volume), and I routinely have people give a light wave to show they heard. In addition, the biggest complaint about cyclists in local social media is about them passing without notice.

Cyclists will normally do the same thing passing out other cyclists at a 5-10 km/h speed difference, and it's definitely useful there.

If you just bell once or twice, and don't aggressively keep ringing, I'd never consider a bicycle bell in a shared space rude. I even consider it good manners, though as others have said, that varies between cultures.

Being visually impaired, though, I'm grateful for cyclists who use their bell. It's immediately clear. For some reason, my brain takes slightly longer to process someone yelling "on your left!" or similar, than just a quick "ring ring".