Y
from Fancyclopedia 2 ca. 1959
Because some scribes of Norman England didn't know enuf about Anglo-Saxon to continue spelling words like "hwaet" with an hw, but instead spelled them wh, the h element has almost disappeared in recent-immigrant-dominated regions of the US like the Atlantic seaboard, and Y and "why?" are pronounced identically. Hence such puns as YFanac.
from Fancyclopedia 1 ca. 1944
Because some scribes of Norman England didn't know enuf about Anglo-Saxon to continue spelling words like "hwaet" with a hw, but instead spelled them wh, the h element has almost disappeared in recentimmigrant-dominated regions of the US like the Atlantic seaboard, and Y and "why?" are pronounced identically. Hence such organizations as the YIAOPUMUMSTFPUSA, Unltd.