This repo has the shell for a simple app that you can put on your phone; when you click a button, the computer speech sythesizer will "say" whatever the button says.
The app uses the Service Worker functionality to cache (save) the page so that it works even when you're offline. But that means that you won't see changes to your code unless you clear the cache. I've added a script to do just that, and you can click the refresh icon to run it.
To make your app say more things, just copy the HTML for one button item, then paste it right below the other buttons and change the button text.
The slides used during the event are at https://docs.google.com/presentation/d/1ZAARgmrUSBrTaIfUEmxyuVo92M1udBjeOLi76as7UQ0/edit?usp=sharing