The spread of computing to every corner of our physical world doesn’t just mean a proliferation of screens large and small—it also means we’ll soon come to rely on mobile computers with no screens at all. “It’s now so inexpensive to have a powerful computing device in my car or lapel, that if you think about form factors, they won’t all have keyboards or screens,” says Scott Huffman, head of the Conversation Search group at Google.Google is already moving rapidly to enable voice commands in all of its products. On mobile phones, Google Now for Android and Google’s search app on the iPhone allow users to search the web via voice, or carry out other basic functions like sending emails. Similarly, Google Glass would be almost unusable without voice interaction. At Google’s conference for developers, it unveiled voice control for its Chrome web browser. And Motorola’s new Moto X phone has a specialized microchip that allows the phone to listen at all times, even when it’s asleep, for the magic word that begins every voice conversation with a Google product: “OK…”There’s nothing new about voice interaction with computers per se. What’s different about Google’s work on the technology is that the company wants to make it as fluid and easy as keyboards and touch screens are now. That’s a challenge big enough that, thus far, it has kept voice-based interfaces from going mainstream in our personal computing devices. And in cases when they are in use, such as interactive voice response systems designed to handle customer service calls, they can be frustrating.