Options I am aware of:
2) Cheap Android Tablet and Android Speech: https://community.smartthings.com/t/android-as-a-speech-alarm-device-released/30282/26
3) Hopeful - Aeon Doorbell - https://community.smartthings.com/t/aeon-doorbell-type-beta/28889/161
Sonos is expensive if all you are using it for is announcements, plus I have heard it can be slow to load the MP3s, I don't have first hand experience with this.
I like the android option, but it is complex and with complexity I expect upkeep and failures.
I have the Aeon Doorbell, but I am not a coder so I am waiting on the charity of the devs to create a device type that can call upon arbitrary sounds loaded on it so it can be queued to tie those sounds to arbitrary events.