Here's how it works: Spritz shows you one word at a time through a narrow, rectangular viewing pane called the "Redicle." That name is a pun of sorts, as each word has one letter highlighted in red (get it?!). In more technical terms, that letter is the "optimal recognition point," the letter that helps your brain piece the word together quickly (and with as little eye movement as possible). The speed is adjustable, too, ranging from 100 words per minute to 1,000 -- far exceeding Spritz's claimed average of 220 words per minute.
Once Spritz releases its SDK, sometime in the coming weeks, developers will be able to build it into their apps, as well as create things like Chrome extensions. (Spritz CEO Frank Waldman says Spritz has no intention of doing this itself, which is probably fine, as 12,000 developers have already requested access to the SDK.). Website owners, meanwhile, will be able to integrate the technology by embedding some simple HTML code.
As of today, though, the GS5 and Tizen-powered Gear 2 are the only confirmed devices that will make use of the technology. On the GS5 in particular, Spritz will be baked into the native email application so that you can read your emails through a viewing pane at the top of the screen. I started out at 240 words per minute (just above the supposed average) and had no problem keeping up. I've embedded a demo gif below -- and don't mind the fact that I'm using a retrofitted GS4 instead of a GS5.
It's a similar deal with the smartwatch, which, when you think about it, is actually a genius place to install a speed-reading app. The idea is that you can speed-read from your wrist if you're in a hurry, but if you want a longer look you can tap a "reply" button on the watch, which will prompt the email to open on your Galaxy phone. Once again, I'm using a last-gen device (the original Gear), as Spritz didn't have any of the new devices on hand. But you get the idea.
Again, that's it as far as officially sanctioned devices go. Still, the Spritz team has been doing some hacking on its own, if only to show developers what the technology is capable of. In particular, the company has cooked up an unofficial version of Kindle for Google Glass, allowing you to read novels and other materials, in addition to whatever you might encounter on regular websites. It's a neat idea, and one I hope Amazon at least considers implementing. Still, it won't be for everybody: after a few minutes of practice, I still struggled to read a simple young-adult novel at 280 words per minute. When it comes to fiction, at least, I might continue to read one sentence at a time, even if I do chug along at a slower pace. But that's just me. In any case, take a look for yourself (and thank the Google gods for that convenient screencasting feature for Glass).