I think this excerpt from Rasmus himself pretty much encapsulates how PHP was designed:
Well, there were other factors in play there. htmlspecialchars was a very early function. Back when PHP had less than 100 functions and the function hashing mechanism was strlen(). In order to get a nice hash distribution of function names across the various function name lengths names were picked specifically to make them fit into a specific length bucket. This was circa late 1994 when PHP was a tool just for my own personal use and I wasn't too worried about not being able to remember the few function names.
Biting the hand that feeds IT
