Earlier quoted context omitted.
This wouldn't work in eg German, where there's no way to cancel out pronunciation like that.
Can you give an example of how this wouldn't work out? I can't even figure out how to make one up, and would like to see how it would look.
DASS/DAS; S=1
BUND=BUNT; D=T
MANN/MAN; N=1
VIEL=FIEL; V=F
VERBEN=WERBEN; V=W
SIEH/SIE; H=1
GANZ=GANS; Z=S
POPP/POP; P=1
That only gives five letters as the identity (H,N,P,S,Z), but that's how you'd attack it.
The equivalence of D/T, for example, is unsurprising as it's an example of voicing changing; these words are in the process of changing.
If you can do more complex work with bigrams, more are possible, e.g.:
JAHR/JA; HR=1; HR/H; R=1