The thing that made Al Bhed a speakable language was more than just a simple cypher, though it may seem so the more you play Final Fantasy X...

The game creators analyzed real language, and what makes it speakable. They realized a few important points.

First off, Vowels have a 1-1 correlation. That means vowels are never replaced by consonants.

Cunno = Sorry.
U=O. O=Y. Y=A. A=E. E=I. I=U. and back to U=O.
You can see how the group of vowels loops around. This is one complete set.

Secondly, many of the plosive consonants have been left as plosives. You can easily see this, as the positions of P and B have been switched, as have T and D, and G and K. So the language 'feels' the same.

Oddly enough, most of the liquids and rhotics have been mixed around with various other consonants, and even the vowel sounding W. This makes the language quite alien, but still pronouncable for the most part. One could easily make a machine-translatable pronouncable cypher, with this type of knowledge.

In Al Bhed;
N=R, R=H, H=N.

C=S, S=M, M=L, and L=C.

W=Z, Z=J, J=V, V=F, and F=W.

It has been mutilated partway, so it seems like a cypher, but with most of the vowels intact, it makes the language seem VERY pronouncable.

Ed ryc paah sidemydat byndfyo, cu ed caasc mega y lobran, pid fedr sucd uv dra jufamc ehdyld, ed sygac dra myhkiyka caas JANO bnuhuihlypma.

Pronounced: "EAY-de raae-ku peahah-ha seeee-deeaymae-deah-te baeaen-de-feaeoh, kuoo eay-de kuahah-see-ku meay-geah ae luoh-bae-raahn, peee-de feeay-de-ra seeoo-ku-de oo-fu de-raah jaeoo-feahm-ku eay-ha-deae-lu-de, eay-de seeae-geah-ku de-raah mae-ha-kukeeae-kukah kuahah-see JAEAHNOH baenoo-haooee-ha-luae-pemah."

Interesting. I'll keep that in mind if I ever decide to create a language lol.

Let's make one then! A pronouncable Vizzed Language. ;P

The vowels would have to stay amongst themselves.
H, is a touchy subjects so I say we should leave it be.
S and Z would have to be switched accordingly so SH and ZH would be switched too.
L and R would have to switch, as would M and N, since those are the liquids and rhotics.

The letters that can be freely switched are then...
A=E=I=O=U=W=Y=A...
L=R=M=N...
and...
B=C=D=F=G=J=K=P=Q=T=V=X=B...
The ones that would exchange directly are...
S=Z
And H isn't switched, to retain pronouncability of all words.

At least, that's for the most pronouncable cypher.
I find that cyphers where some letters remain original are quite difficult to crack, as people expect them to be different than what they are!

When I think of them I think they are communists or something. You don't want them to be friends with. Its like the those Iraqies.

So , L can be R or M or N. Why dont we make it a definate thing.. sorta.. Like, L is R and M is N

That's when we're actually constructing the language, which I have laid forth the boundaries for, and you have started. So, lets!

If L was R, the Japanese people could still understand what we were saying.
Lets make L into M, and R into N.

How's this:
[Real letter = Cypher letter]
[Al Bhed coincidences in Green]
H=H
A=O, O=I, I=E, E=U, U=W, W=Y, Y=A

L=M M=L

R=N N=R

S=Z Z=S

Q(u)=X X=Q(u)

B=T, T=G, G=P, P=D, D=K, K=B
C=F, F=J, J=V, V=C

We should call it... Çelphish.

Yu zhiwmk omm zduob er [Çelphish] riy!

Haha, "We" is translated as "You"!
"You" is "AhYou".
"Us" is "Ooze".
His and Her become Hez and Hun.

How does Us become Ooze? Im trying to follow, but its hard...

Because U becomes W, which sounds like 'oo'... and Because S becomes Z, so it sounds like 'oo-z'. Ooze!

Ohh, i thought u litral mean it was spelt like that, sorta... U know what i mean.

Nope.

"We" is translated as "Yu"!(you)
"You" is "Aiw".(ahyoo)
"Us" is "Wz".(ooze)

Do you reckon with time, we would really be able to say that fluently?

I reckon revisions could be made. I picked arbitrary values, knowing that certain letters had a ton of exceptions. The word 'you' is made of all vowels, and when you think of it, many people would say 'fly' is made of all consonants. Certainly 'Shh' is.