The Moto X is a pretty great device, even if it didn't turn out to be the mythical beast many of us were hoping it to be. However, one feature the device ships with is pretty unique. It's always-listening and you can talk to it whenever you want and have the device perform actions with little intervention from yourself. How Motorola and Google have done this is through a combination of hardware and software. The hardware is pretty essential, however as the device features a special X8 processor that has a CPU core that's always listening. Which is why the Moto X has such great battery life even with this always-listening technology.
This technology could well be headed to Android 4.4 and Google Now. The Nexus 5 leaks that have been coming from Italy detailed a device that apparently responded to "OK Google Now" from the device's homescreen but, there's no photographic evidence to support that. As SlashGear notes however, Always Listening is a feature in Qualcomm's Snapdragon 800 CPU. The very same that's rumored to be at the heart of the Nexus 5. While this isn't the first time Google has used a Qualcomm processor for their Nexus, this choice could have more to do with always-listening than performance.
Of course, if this feature is coming to Google Now in Android 4.4, then it'd only really work with devices running a Snapdragon 800, right? Which would cause Google some headaches when their partners update some of their latest devices, right? Well, in the second half of 2013, we've seen a large amount of devices launch with the Snapdragon 800. The Galaxy Note 3, the LG G2, Sony's Xperia Z Ultra and Z1. While manufacturers can't go back in time and update their devices with a Snapdragon 800, KitKat will still be heading to those devices but, perhaps without always-listening capabilities.
Nevertheless though, we shouldn't have too much longer to wait for Android 4.4 and the Nexus 5. Google Now has quickly become a big deal for Google and we're sure that in Android 4.4, Google Now gets that little bit sweeter.