Lets talk more about text input. What is common between the existing methods?
My first try culminated in the categorization of text input methods into four groups:
2-Drawing methods (grafitti, gesture for drawing)
3-Virtual keyboards (swype, virtual pointing)
This classification is far from being complete and definitive. Some techniques can combine more than one input method or can be considered borderline. For example, you can activate virtual keys by using gestures, your eye, touchscreens or hand poses. However this classification is enough to provide a start point for analysis.
Keyboards are good for several reasons: you can use your 10 fingers, have a clear confirmation when the letter has been input and can use your muscle memory to type without looking at the keyboard. Drawing techniques such as Graffiti are good because they can leverage your knowledge of writing and the letter shapes to memorize a large number of commands easily. Virtual keyboards use the fact that they are not real to improve input by changing the way you activate the keys. Finally voice recognition use the association of phonemes and written text to allow you to input text.
Each technique has different advantages and weakness. Graffiti may be slower than the keyboard but it is very fast to learn and can be used in constrained spaces. A good thing to do before going further is to try to establish some guidelines and principles that we can use to guide decisions later. After thinking for a while, I came up with the following dos and dont's for text input methods:
Ideally we would want something that is fast to learn and use. Something as intuitive as drawing a letter and as accurate and fast as the keyboard. When we consider the application in virtual environments, where the user does not have a physical keyboard, further restrictions apply.
Many interesting ideas are ruled out from the beginning because they simply add more complexity to an existing input system. If you are selecting a letter, anything more than just pointing at it will not present a real gain. The only exception would be just looking at it instead of pointing with a device or your hand.
If we want a method that is easy to learn we are pretty stuck with using a common known letter layout (qwerty or alphabetically), speech or drawing.