What Apple does differently:
alef-damma is A and M
your p is their B
your S is their c
your D is their C
your d is their d and V
your dh is their D and v
your ' is their e and their G
your gh is their E and their g
your q is their F
your H is their h and X
your kh is their H and x
ya without the dots is their I
your i is their i
the 'che' sound is their J (che as in ahmad chalabi)
the 'gaf' sound is their K
your th is their N and [
your h is their o
ة is O and p
your t is their t and P
ے is U
your sh is their w
the pause diacritical (I can't remember their names) -- ّ -- is their W
your T is their y
your Z is their Y and ]
the persian 'r' with three dots -- ژ -- is their Z
hamza is shift-2. heck, here's 1-8:
١ ! ٢ ء ٣ أ ٤ آ ٥ إ ٦ ئ ٧ ؤ ٨ ى