Options I am aware of:
- Sonos
- Cheap Android Tablet and Android Speech: Android as a Speech/Alarm Device released! And Updated!
- Hopeful - Aeon Doorbell - Aeon Doorbell Type Beta
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.