The speaker comes home from college without a degree, feeling like a failure and still afraid of schools. They compare themselves to the "parabolic parodical son," a twisted echo of the prodigal son who returns home. Then the poem turns to grandpa, who also had a breakdown in college. He never finished either, but he seems settled now, with a good pension and shelves of books on medieval warfare.
The title, "Palilalia," names a speech habit of repeating one's own words, and the last stanza uses it as an image. History, the speaker says, repeats itself by stammering, like a child who whispers the same words again. The speaker was that child at seven.
The mood is quiet, wry, and a little tender. There is embarrassment and fear, but also some comfort. If grandpa's life turned out fine, the speaker's might too. The repetition feels less like a curse than a family pattern the speaker is starting to recognize.