The Qwerty keyboard originates from the 19th century and is still widely used. As far as my knowledge goes, the touch screen was not yet invented at that time, there were only massive type writers with hammers which could occasionally clash. In fact, the Qwerty layout was designed to be as tedious as possible, to minimize the chance that two hammers would collide. These days Qwerty is obsolete, almost no one has an old style type writer. Still it's used for convenience, while more ergonomic alternatives are available. Dvorak, for instance, is the most well-known alternative layout, which is supported by almost every major operating system.
Qwerty also doesn't seem to be very suitable for touch screens. All these buttons crammed on a small screen is a source of frustration because it's easy to place your finger half a centimeter too far to the right, pressing the wrong key. I remember the first time I tried to enter my own name on a touch screen, it was no fun at all.
Due to the more open nature of Android devices, it's possible to replace your keyboard with something else. Every author of a keyboard replacement claims that their input method is faster than a regular Qwerty. There are quite some alternatives to be found in and outside the Android Market, and I gave them a try to see if there's something better than the default keyboard.
Since I'm bilingual, it's pretty important that a keyboard allows me to quickly change the language. If I need more than one tap to change the language it's actually too much. Auto-completion and auto-correction should also be available. Most keyboards supporting these features work well with the English language, but these features should also work for Dutch.
The default keyboard of my Android device, the HTC Desire, comes with a few tricks to overcome this limitation. It's called Touch Input and supports auto-completion and auto-correction. Since the update to Froyo (Android 2.2) it's easy to switch languages, a small button on the bottom row allows me to switch with one single tap. A slight annoyance is that auto-completions appear near the word you're typing. I have to reach quite far to select a word. Still it's not a bad keyboard at all, it fits my criteria quite well.
This alternative keyboard has been around for quite some years on a number of platforms. Recently, they also published an Android version, which is for free in the Market. The keyboard consists of nine main buttons (with some helper buttons), where each has one of the nine most common English characters. The remaining characters can be "typed" by moving your finger from one button to another. For example, to type a "d" you move your finger from "o" to "e". A major advantage of this approach is that this allows you to type with one hand, without making too many errors.
However, MessagEase doesn't ship any dictionaries, which makes the typing exercise still a bit tedious. It does come with a set of different layouts, optimized for the character distribution of wide spread languages. Dutch is not available, but that's not a big deal since its distribution is quite similar to English.
There's not much to say about this one, it's just annoying. The idea is that buttons which are likely to be pressed next become larger while you type. It violates one of the major usability corner stones, stating that a user interface should not change dynamically. I didn't manage to maintain a proper typing speed because the keyboard changes between targeting for a button and actually touching it.
Yet it offers auto-completion and auto-correction (the latter will be no luxury).
So in short, stay away from this one. Unless you want to be laughed at by your friends seeing you failing at typing a simple sentence.
One of the most innovative keyboards I have seen so far is 8pen. No more Qwerty, but a colored cross creating a space with four quadrants. See the video below to see how it works.
I gave it a try, but decided to drop it due to the typing speed. I cannot imagine that a gesture is faster than locating and tapping a character on a normal keyboard. I did a small benchmark, where I typed The Quick Brown Fox Jumps Over The Lazy Dog. It took me 21 seconds with the default keyboard (Touch Input) while it took me 90 seconds with 8pen. Before the test, I practiced for a considerable amount of time. Certainly not enough to become fluent with it, but at least I knew where the characters were to be found. I could not imagine I would become more than 3 times faster with this keyboard in order to beat my Qwerty-time, so I dropped it.
Some advantages are that this keyboard is quite suitable while holding it in one hand and that the keyboard can be made tranparent. There's an English dictionary which provides suggestions.
Actually this keyboard should have been my favorite keyboard, since it's free software (Apache 2.0 License) and comes with a big pile of options and add-ons for additional languages and layouts. It's the only keyboard I could find which supports the Dvorak layout, still I doubt whether it makes sense on a touch screen. It comes with suggestions and corrections and enough configuration options to fine tune the behavior of this keyboard.
The reason not to choose this keyboard for me was that changing the input language is clumsy (long press and going through two pop-ups). Otherwise it's a nice keyboard, although it's probably a bit too geeky for the average user.
Swype is a (much) hyped keyboard, which predicts words based on how you move your finger over the keyboard. It looks like an average Qwerty keyboard, and you can use it as such, but the swiping is what this keyboard is all about.
I must say I haven't used Swype intensively, because it lacks support for Dutch. Still, it's easy to use and it's stunning to see how often it guesses the right word, even when you were very inaccurate.
This keyboard has become my personal favorite. At first glance, it looks like a normal Qwerty keyboard. But the word suggestions are the best I have seen. There's some artificial intelligence involved to show the best suggestions, which are presented just above the keyboard. A Dutch dictionary is also available, with a set of rules with common word combinations. What I really like is the amount of 'taps' I have to make to change a language: none. It looks through all available dictionaries simultaneously and takes the word combinations into account. It also has the ability to learn words and the order in which you type certain words, which makes its usage even more efficient over time.
There are some small annoyances, though. When you hit space it will auto-complete (or auto-correct) the word based on the middle suggestion. This is not always desired, so you hit backspace to restore it. This is where Touch Input shines: it restores the character sequence you typed and it allows you to ignore the auto-correction. SwiftKey doesn't do this, and there's nothing else you can do than retyping the word and be careful with the space key. I hope this will be addressed soon.
SwiftKey is not free, but there's a trial version available which allows you to try it for free for one month. For me, it was worth the money, given its mind-reading capabilities. Besides, it's on sale until the end of this month (January 2011).
A new version has been announced, with better prediction capabilities and improvements in the field of autocorrection.