[sjnhjjjm] c q x ch sh th

English has 3 redundant consonants: C Q X.  The sounds those letters make can be spelled with other letters.

English has a bunch of digraphs, but 3 of the most common are CH SH TH.  These create sounds not otherwise easily spellable with other letters.

It's tantalizing to try to map the two sets to each other.  Here are some commonly used partial maps:

C-CH in Italian. X-CH from Greek chi (though it is pronounced k). Q-CH in Chinese transliteration.

X-SH in Chinese transliteration.

TH is a rare consonant among languages, so nothing common maps it.  I think I've seen Q-theta in a Greek input method, and capital Q sort of looks like theta.

These constraints together do result in C-CH, X-SH, Q-TH.

However, it's unclear what this could be useful for.  Problems:

As output, e.g., QE is the new spelling of THE: Losing redundant letters causes etymology to be lost and consequently meaning.  They had also been used to distinguish homophones.

As input, e.g., typing Q results in TH being input: You are still going to want to input literal Q C X to spell existing words that use them.