What is a voice assistant, and what can it do?

A voice assistant is the software — Amazon's Alexa, Google Assistant or Apple's Siri — that lives inside a smart speaker or display and responds when you say its wake word. Once set up, you can ask it to play music, set timers and alarms, answer questions, check the weather, add to shopping lists, make calls and, crucially for a smart home, control your other devices: "turn off the bedroom lights," "set the AC to 24," "switch on the geyser." A plain speaker does all this by voice; a display adds a touchscreen for video calls, recipes, photos and camera feeds. Think of it as the hands-free brain that ties your smart devices together and makes them convenient to use.