I'm reading academic articles for my "U.S. Music History I" class (~1650~1900). Now, I have just enough music theory that I could sit here for a few minutes and figure out this passage. But what's the point, anyway?
Besides his often repeated scheme of following major by minor, he frequently reiterates a passage by an abrupt step to the submediant. Sometimes he does this by substituting, for the tonic triad of his major key, a tonic four-two chord, with the seventh flattened and with the bass resolving it on to the root of the tonic of the major submediant key. He does this in his last work, a duet for tenor and bass, dated February 27, 1813. In this, having reached the submediant B major from D, he stays for sixteen measures in related keys, and then modulates back to his tonic by following the dominant seventh of B with the mediant seventh of D (that is, by merely altering the note A-sharp to A-natural), following this with the dominant seventh of D, and going thence to the tonic.
We're assigned about four articles every day. They're not all this technical, but they're all pretty stuffy and boring.