Starting today, Google Assistant just became even more useful than ever. From this point on, you can use it to broadcast messages throughout your house - stuff like "it's time for school" or "breakfast is ready", you get the gist. You can create such a broadcast message from any device with Assistant - say your phone or a Google Home device. The message will be broadcast by all the Assistant-enabled speakers in your home. Simply say "Ok Google, broadcast" immediately followed by your message. There are special effects for some things - if you say "Ok Google, broadcast it's dinner...
Source: https://www.gsmarena.com/google_assistant_now_broadcasts_messages_throughout_your_house_on_all_speakers-news-28230.php
