This is partly an exercise to see if I understand passphrase generation from a given dictionary using the DiceWare technique. But also for possible personal usage.
All three-letter word lists I can find generally involve words allowed in Scrabble and almost all include 1014 words. I would reduce this list to 972.
If I now include all combinations of capitalization of these words in my dictionary (all lower, 1st upper, 2nd upper, 3rd upper, 1/2 upper, 1/3 upper, 2/3 upper, 1/2/3 upper), that would give me 972 x 8 = 7776 words. The right amount for a 5-dice DiceWare dictionary. I can now use 5 dice to generate a passphrase.
This would minimize typing, though I'd have to use the shift key a lot, which probably negates any gain.
I also wouldn't have to type spaces since there is no chance of a combo word of six letters being in my dictionary, right?
Even though the number of entries in my dictionary is 7776, the number of words is only 972. Does this give a cracker any advantage?
(7776^1+7776^2+7776^3)/(7776^1+7776^2+7776^3+7776^4) ~= 0.013%
, about 1/7776th of the keyspace.