Following on from the recent posts surrounding difficult text entry on the iPhone, I've been thinking how to solve this. The logical route suggests placing a number of most frequently used letters with some treatment (either size or colour). There's various opinions as to what these are from Samuel Morse (1791-1872) to calaloging all words in the Concise Oxford Dictionary.

Depending on positional layout (with QWERTY) a select group of these frequent letter (>5%) should be considered for prominence:

E - 11.1607%
A - 8.4966%
R - 7.5809%
I - 7.5448%
O - 7.1635%
T - 6.9509%
N - 6.6544%
S - 5.7351%
L - 5.4893%

I'll post the results from the initial layouts soon for review