Last year, Amazon unveiled a new announcement feature for echo devices and later expanded to Alexa-compatible Sonos speakers. This feature is now available on all devices that use Alexa.
This feature allows you to switch your Echo device to the intercom system by default and initially roll out to Echo, Echo Plus, Echo Dot, Echo Show, and Echo Spot. Users send announcements saying "Alexa announcement / everyone / broadcast …" and their messages are pushed simultaneously to all devices in the home network.
Amazon says Announcements offers "a new product that has passed the certified Alexa built-in products and the self-tests and certifications that are provided." Now this feature is compatible with Alexa, such as Amazon Firebox TV Cube, Sonos Speaker, Facebook Portal and others, which will be broadcast to any device that may be at home.