( i’ve moved this to projects so you can get answers specific to your own requirements.)
There are many different ways to do this with SmartThings, and many different possible devices you can use, but several of them have quite complex set up’s. For example, you can get this with an echo or Dot with one of two smart apps (AskAlexa or EchoSistant), but both will require that you set up an Amazon developers account, and can get pretty complicated.
Probably the easiest way to do it is with the $49 Aeon Labs Doorbell, which can play up to 99 different custom MP3 files, so you can have different notifications for different SmartThings events. Only thing is that one isn’t very loud, it’s intended to be regular doorbell volume. But it’s definitely popular.
There are lots of other options, too, and they vary in technical expertise required.
LANnouncer is another option which is probably midway in complexity between those two and can run on any android device, including just an inexpensive tablet.
If you use the quick browse lists in the community – created wiki, look under projects for “voice” and there’s a list of project reports there and you can see what other people have done.
You can also look at the quick browse lists in the smart apps section for voice.
So, lots of choices, but it just depends on exactly what you’re going to want and how much set up work you are willing to do.