I suggested it in chat.
Basically, a selection of random numbers, maybe 6 or 9.
Each number represents a cross-section of the alphabet, and could be displayed like the keys on a phone.
Each number can be used only once.
A possible unique feature would be that if a 1 came up, like on a phone it could represent a space, and therefore two or perhaps three words could be declared.
Numbers, I'm open to suggestions.
Maybe something algebraic, going with the mixing of letters and numbers. Not sure what way you could work that though.