I have succeeded with every letter but J. Some people submit that the J is silent in "marijuana" or "hallelujah" when, in fact, they are voiced not as the usual [d-zh] diphthong. The "ju" digraph in most -juana words is voiced as a W, while the j in hallelujah is voiced as a y. Some say V is never, ever silent, but I submit that the second V in the word "savvy" is, in fact, silent, since it is pronounced SA-vee, and not SAV-vee. Here is "my" alphabet:

a: boat
b: dumb
c: scene
d: Wednesday
e: once
*f: halfpenny is not American, but IS English (and though many people do pronounce the second f in “fifth,” it is not incorrect when pronounced “fith”)
g: gnostic
h: hour
i: business
j:
k: knowledge
l: would
m: mnemonic
n: autumn
o: phoenix
p: pneumonia
q: lacquer
r: macabre
s: island
t: ballet
u: guide
v: savvy
w: answer
x: faux
y: day
z: rendezvous