Orfogramma

Awful grammar? Languagehat has a great post about a Russian term, "orfogramma", which means a point of uncertainty in the spelling of a word, a place where you can't tell from the sound alone how to write it.

One comment stated that which was obvious to me:

I suppose though that in English "letter which must be determined by
orthographic rules rather than sound alone" is almost synonymous with
"letter".

In other words, English spelling sucks. Or as Mizuki says, "English is crazy business!"