Well, today he explained to me lots of things around pronounciation based on spelling.
For example situations in which "и" is pronounced "ы" depending on spelling, and lots of tips around differentiating between "щ" and "ш" which I find a bit confusing. Last week he told me all about "ъ" which I had misunderstood, for example the difference in pronouonciation of a few words in which ъ is the second letter. I did not know anything about that. He said it would be valuable for me if I memorized all spelling rules.
That's not actually spelling. That's graphics and pronunciation. It is useless and very hard to remember all the spelling rules.
Could you tell those words with ъ? сел - съел?
I don't know why is the ш - щ distinction more difficult than л -ль, м - мь?