Adding speaker to CCTV to broadcast live audio remotely (to deter intruders)

I was wondering if anyone had any experience with adding a speaker to a property so when the alarm is triggered and a user notified they can broadcast their voice to tell the intruders that the police are on their way. This would be a live stream of what the user is saying into their app rather than a pre-recorded message. Simpler the better!

Cheers

https://www.youtube.com/watch?v=B57KJ-o8RFQ

Bang on :D