Truthentongue is a keyed caesar that canon characters sometimes use for a "language." The key is unknown at the moment.
Truthentongue characters to the left, regular characters to the right. This would be used to decrypt messages sent in Truthentongue.
A=Y
B=P
C=L
D=T
E=A
F=V
G=K
H=R
I=E
J=?
K=G
L=M
M=S
N=H
O=U
P=B
Q=?
R=N
S=C
T=D
U=I
V=?
W=F
X=?
Y=O
Z=W
Regular letters to the left, Truthentongue to the right. Would be used for encrypting
A=E
B=P
C=S
D=T
E=I
F=W
G=K
H=N
I=U
J=?
K=G
L=C
M=L
N=R
O=Y
P=B
Q=?
R=H
S=M
T=D
U=O
V=F
W=Z
X=?
Y=A
Z=?