The Reflex Typing method allows users to write to a computer in English with a mouse-sized, one-hand keyboard.  The cues in Reflex Typing become self-evident quickly as they correspond to the vowels of the alphabet, which are well spaced within the alphabet as a whole.  The Reflex Typing alphabet is simple to learn and easy to use with the vowels corresponding with fingers and thumb use:  

A, E, I, O, U correspond with the numbers 1 (Thumb) through 5 (Little Finger or “Pinkie”)