긴 영어 문장들 해석이 어려워요

“To those whose education, however admirable in other respects, had provided only rudimentary language skills, he seemed a marvel.”에서 쉼표 사이를 먼저 해석하면 될까요?
“This is all the more confusing as language is much more complex than, say, simple arithmetic, which often takes years to master.”는 주어와 동사가 어디까지인지 모르겠어요.
“Many years later, lecturing at school”은 ‘수년 후 학교에서 강의하면서’라고 해석하면 될까요?
“He made a number of what he called 'A' discoveries about the structure of languages”도 어렵네요.
도움 부탁드려요.