Kumar Rangarajan was driving when he heard his daughter call out to the car speaker. “Alexa, lower the volume,” she said. Now, the car wasn’t really the domain of Alexa—Amazon’s voice-controlled digital assistant—and the volume didn’t come down, but the moment stayed with Rangarajan. In fact, it was instrumental to his shift from the US to India to start Slang Labs with co-founders Giridhar Murthy and Satish Gupta. “I was really unimpressed by Alexa initially. Then one day I found myself trying to switch off the lights in my house by telling the voice assistant to do it. That’s when I realised that voice could be the future of interfacing,” he says.