Google acquired Nest for billions, and then Facebook spent several more billion on Oculus VR. We’re only a few months into 2014, and already billions have been spent by some of the world’s largest digital players, with each of these companies eager to own the next big thing. Mobile is right here, right now, but everyone knows that very soon, there will be something else. But what else?

In the battle to find and claim the next device that everyone will want, these companies will soon realize that next big thing is not a thing at all: It’s your voice.

Voice control suffers from the same things plaguing augmented reality or virtual reality: It has been around for so long that we think we know what it is. Any fan of Star Trek: The Next Generation knows that voice control involves invoking an invisible computer with a command, “Computer,” followed by a query, “How many Klingons does it take to screw in a light bulb?” Maybe that’s a question you don’t want the answer to, but the computer — as voiced by Majel Barrett in the TV series — would know it.

It’s possibly a long history of popular depictions of voice control that made us collectively show so much enthusiasm for Siri when Apple first debuted it in 2011. It’s also partly to blame for why we quickly turned on Siri, declaring her soothing semi-robotic tones to be merely amusing at best or irrelevant at worst.

When Microsoft recently announced its long-rumored Cortana voice service for Windows Phone 8.1 as a catch-up to both Siri and Google Now’s own voice interface, the interest was modest, perhaps because if Siri hasn’t changed the way millions of Apple users use millions of Apple devices, how can Microsoft initiate a wave of behavior change when it has so few Windows Phone users?

But look more closely at items in recent news, and you’ll find voice control surging in a most unexpected place: Amazon. In two unrelated announcements, Amazon made it clear that the company understands the coming power of voice and that it’s prepared to take steps the other digital firms cannot. The first sign was the inclusion of a microphone in the remote control for the company’s new video streaming box, the FireTV. Designed to let you search the video streaming box for movies and TV shows, nothing will stop Amazon from soon having you press the microphone button to say, “Buy that KitchenAid mixer,” in response to an ad you just saw on TV. Through the magic of audio fingerprinting, Amazon could do that even when you’re not watching video through the FireTV box.

How do we know Amazon wants to enable voice-based purchasing? Because at the end of the week, Amazon announced Amazon Dash for its Amazon Fresh grocery service. The Dash is a small gadget that can scan product bar codes to replenish products when you need them or — because it also contains a microphone — can let you issue a stream of products you want added to your shopping list. Press the microphone button to start, say “Milk, eggs, butter” — releasing and repressing the button between each item — and the items end up on your shopping list. For now, you have to go to the website or app to manually move those items into your shopping cart. But that’s just because Amazon is training you to get the hang of it.

I recently predicted that Amazon would likely launch a collection of microphones you would place in key points in your home — one on the bathroom mirror, one in the car, one in the kitchen — and that the company would be smart to charge as little as $40 for a three pack of these microphones. Amazon understands the importance of microphones even more than I thought, however — the company has made the Amazon Dash free to its Amazon Fresh customers who request one.

Because Amazon makes money each time you purchase something using it, the company will have stronger motivation to get you hooked. Apple can’t charge you for Siri, and Google won’t make you pay to use Google Now. Plus, those other services, other than being useful for dictating text messages, can never offer you the convenience of purchasing products wherever they come to mind, in front of the TV, in your closet while getting dressed, or in the laundry room when you realize you’re running out of bleach.

What Amazon will ultimately build using this tool is the world’s deepest customer relationship, one which you would never replace because of its wide-ranging utility. Why switch to Cortana when Amazon’s voice service — I call it Amazon "vox" for now in my new report, until Amazon gives it an official name — can do so much more for you? This realization is what will kick off a whole new effort from Google, Apple, and Microsoft to fight back. They may even call Target or Wal-Mart to see if together they can be as continuously relevant as Amazon will soon become.

In the long run, these microphones will do much more than accept dictation or product requests — they’ll be set to continuous listening mode, and by listening to our daily patterns, they will generate deep insight into who we are and how we like to live our lives. Coming full circle, Amazon may even recommend a book on how to talk to your teenager after it notices that you’re losing your cool more often than before. Better yet, Amazon will build application programming interfaces (APIs) that will allow Deepak Chopra to build a personal coaching service that listens to you, identifies behaviors you need to change, and institutes a six-week training session, monitored continuously by vox.

A service that knows you, anticipates your needs, and can sell you whatever you need to meet those needs — that’s why embedding microphones into your life will enable the next big thing. Whoever owns this service owns the customer, probably for life. No wonder Amazon wants to get a jumpstart on its peers.