I think that English spelling is not quite as hairy as English pronunciation (do you start the name of the language ‘en’, as in pen, or ‘in’ as in pin?). However, it is still far from rational or predictable. We learn little rhymes at school to help with spelling but did you know that the most famous one, “i before e, except after c” is wrong most of the time.
You can read an online article (Specktor, B. 2019) about this from Reader’s Digest. However, I’d already figured that out myself after a discussion Jane and I were having this afternoon by downloading a word list (see words.txt in this GitHub project on english-words). I searched all 466,551 lines using grep and wc to pick out how many words (eg.
grep -i 'cie' words.txt | wc -l) contained ‘cie’, ‘cei’, ‘ie’ and ‘ei’.
My findings were about four times as many words containing ‘ie’ as ‘ei’ (16,412 to 5,611) and about three times as many with ‘cie’ as ‘cei’ (867 to 302). There were 146 reified examples with both ‘ei’ and ‘ie’ but few were likely to be heard in conversation. I think the takeaway is to forget this rule of thumb; if in doubt, consult a dictionary.