How voice-activated devices listen to you (and how to turn them off)

USA TODAY's Ed Baig tests Amazon Echo's personal digital assistant. Find out how Alexa relates to Siri, benefits and flaws in this Jan. Siri can now name songs, via Shazam. SAN FRANCISCO -- While there are multiple voice-controlled products, only a few are in wide use in the United States. Siri can be set up to only turn on when the user pushes a button, or to also respond to the phrase "Hey, Siri."