Using a simple 9-button keypad, Thumbscript (TM) allows users to rapidly
enter (with one hand) and send text via any mobile communication device.
Thumbscript is based on a visual connect-the-dots so letters are entered by
pressing once where the stroke of a letter begins, and a second time where
the stroke ends. The language also includes one-key commands for special
functions like delete, shift, and return while numbers 1 - 9 are nearly
identical to the layout of a telephone. 

http://www.thumbscript.com/