Hey, Alexa, what can you hear? And what will you do with it?

In one set of patent applications, Amazon describes how a "voice sniffer algorithm" could be used on an array of devices

Amazon ran a commercial on this year’s Super Bowl that pretended its digital assistant Alexa had temporarily lost her voice. It featured celebrities like Rebel Wilson, Cardi B and even the company’s chief executive, Jeff Bezos.

While the ad riffed on what Alexa can say to users, the more intriguing question may be what she and other digital assistants can hear — especially as more people bring smart speakers into their homes.

Amazon and Google, the leading sellers of such devices, say the assistants record and process audio only after users trigger them by pushing a button or uttering a phrase like