For Canadian and U.S. owners of Amazon Echo speakers, you can now turn your speakers into a one-way intercom system. The setup of Alexa Announcements isn’t complicated. All you need to do is talk to Alexa and say things like, “Alexa announce that dinner is ready.” And then all the Echo devices in your home will make the announcement. Or you can use other hot words like “Alexa, tell everyone…” or Alexa, broadcast…” It isn’t clear yet if this will work on other Alexa-enabled devices but for now we’re assuming it’s only for Echo speakers.
Source: Android Authority