Microsoft provided an interesting post to the Building Windows 8 Blog yesterday that focuses on the design of the touch keyboard in Windows 8. The contents of this post are largely theory to most people, since so few have touch-based Windows 8 PCs and devices. But the decisions that went into this important piece of software will impact hundreds of millions of people in the years ahead.

Fortunately, it looks like Microsoft made some good decisions.

In Designing the Windows 8 touch keyboard, Steven Sinofsky writes:

Starting with the earliest Tablet PC enhancements to Windows, we have been working on “on-screen keyboards.” With Windows 8, we started fresh and took a "first principles" approach to developing the touch keyboard. Given the amount of experience many of us have with touch keyboards for phones, and the myriad of touch devices we interact with these days, we set a very high bar for the quality of the experience and effectiveness of input with the new Windows 8 touch keyboard.

Paul explains:

Despite years of experience with the touch keyboard in Windows, Microsoft started over with the version in Windows 8. This was the right approach.

Since most of this post, which was written by Kip Knox, deals with the “why’s” of the design of the Windows 8 touch keyboard—and in this case, Microsoft does seem to be offering actual reasons rather than excuses—let’s just boil it down to the pertinent bits that will impact those moving to Windows 8 and, hopefully, touch-based screens in the future.

Designed from scratch. Microsoft’s previous attempts at on-screen keyboards were correctly judged to be abysmal and jettisoned in favor of an all-new design that was informed by peoples’ experiences with modern touch-screen devices (smart phone, tablets).

High-level goals. Fairly obvious, but Microsoft wanted the touch keyboard fast, reliable, and comfortable.

Key layout is optimized for two-handed typing. While some will continue to hunt and peck, Microsoft optimized the layout of the touch keyboard for the same two-handed style of typing that people use with a real hardware keyboard.

Optional thumb keyboard. An optional split design, called the thumb keyboard, is designed for holding a tablet with two hands and typing with your thumbs. In this layout, the placement and shape of the keyboard parts was determined by comfort research with sensors.

Adjustable size. You can adjust the size of the touch keyboard to accommodate different hand sizes.

Optimized for glass. While typing on glass has many downsides (compared to a physical keyboard), Microsoft used software to minimize these. For example, the keys change color when you touch them, and trigger a subtle sound, mimicking a real keyboard. And to overcome the “sloppiness” and inaccuracies common to touch keyboards, Microsoft designed the one in Windows 8 to intelligently correct errors as you type. Other touch keyboards have auto-correct, of course.

Optimal layout based on language. The default layout of keys on the touch keyboard various by language and is based on which keys are most needed. The number keys do not appear on the default layout but are reached via a symbol/number key and are then laid out like an ATM number pad (the reverse of a typical hardware keyboard, but more common and familiar to today’s users).

Press and hold. One of the cool features of the touch keyboard—one that’s also present in the Windows Phone touch keyboard—is a “press and hold” action in which you hold down on a key to trigger a pop-up with additional keys. So, for example, you can hold down on the “E” key to see variants of that letter with different types of accents and other adornments.

Multi-touch view peek. In an interesting take on press and hold, you can press and hold with the symbol/number key (&123) and, while continuing to hold down the key, select symbols or numbers with your other hand. Then, when you’re done, release the key with your first hand.

Testing and research. Microsoft tested the hell out of this. Of course they did.

Emoji key. That little happy face key is called the “emoji” key: It triggers the emoji view, which consists of emoticons (or, more correctly, “emoji characters”) from which to choose. Do not ever use this key. Ever.

More to come. Microsoft vaguely promises to make “a few more improvements” to the touch keyboard (or “the typing experience”), though it’s unclear when, or how, these changes will be made.