“You will see the World War I artillery acronyms are shorter, but, that is because, you have to remember, that, the primitive radio-transmitters that sent the Morse code were run by batteries, and, those didn’t last much more than a half-hour tops, probably less.

“Thus all World War I codes had to be S-n-S, Short-n-Sweet.

via BBC News – Has World War II carrier pigeon message been cracked?.