Wow, this is awsome. I wish I had this to build off of before I wrote my RPi device a little while ago. With a little bit of code and a couple apt-get’s, you could plug a speaker into your pi and get it to work with “Speaker Notify With Sound”.
Check out my setup here. RaspyThing
I know it’s a little rough around the edges, but I’ve got it working to alert when any door is opened, play the weather forecast in the morning, and announce all three of my kids bedtimes. I wish I could have figured out json like yours.