Interchangeable ch/sh and k/t characters

[Aga Tentakulus]

Pairs of letters - ch/sh and k/t, not bigrams.

I don’t understand your point of view.
The way I see it, there are two combinations and two individual characters.
But they aren’t the same as, for example, ‘9’ being written as ‘us’. Here, it’s an abbreviation and not a ‘g’.
You need to understand everything, because nothing is really the same.
So ‘4’ and ‘q’ aren’t the same.
I can already hear you saying, ‘It’s the same thing.’
But it isn’t, because the truth is, it’s already been done that way.
   
That is cryptology.