two things - first, shouldn't this pattern be はおろか (no う)? And if that's the case, the meaning should be more 'not to mention A,' or 'let alone A' (ie 1ドルはおろか１セントも持っていない I don't have a cent , let alone a dollar)
That description nails it more precisely, thanks. I updated the ひらがな and the meaning; let me know if you feel like the meaning could be improved upon any more!
the order seems reversed between English and Japanese (isn't everything??) so to help myself remember I'm using "let alone a dollar, I don't even have a cent" which whilst somewhat idiomatic in English has the advantage of keeping the Japanese sentence order
"Shows that not only B is true, but A (which is less desirable) is also true."
I think this is false that A is less desirable. In the provided example, "漢字はおろかかなも読めない" it's obvious that when you're saying "let alone kanji, I can't even read kana," reading kana is the minimum standard that is failed and reading kanji is not even in the question.
Here, the (B) part of the sentence being the minimum standard which makes (A) not even worth asking implies that (B) is less desirable. It is less desirable to "not even be able to read kana" than to merely not be able to read kanji, which is not even worth mentioning if you can't read kana.
