Reading to Cal yields some combination of that imaginary moo — a vicarious confirmation of being heard and understood — and the more conventional verbal affirmation I get from reading with Simone.

But reading aloud in this way, to and with my children, still feels like a new experience. I had to train myself — it took a couple of years, honestly — to be able to say the words on the page and to also take them in, to understand them, as I would if I were reading alone, to myself, in my head. It’s a many-layered pleasure, chiefly because, unlike with movies, one can supply one’s own images, one’s own sensory details. And I’ve learned some strange things about myself from paying attention to how I do this. For instance, I do not imagine fictional characters as having facial features — in my mind, though I can smell characters and touch the fabric of their clothes, their faces are blank, gray patches. I often wonder why this is and what it says about me.

As a parent of a child with special needs — who is, in special-needs parlance, “very involved,” meaning deeply affected, extremely different from me — a central question of my life is what he is understanding, how differently he apprehends the world. When he hears words, what do they mean? All the context for language that my life — that a typical life — has provided doesn’t apply to him. When he hears the word “red” — he also has cortical vision impairment, meaning that his eyes work perfectly, but they’re like windows his brain isn’t always looking out of — he can’t possibly envision what I do.

We’ve come to the part of “The Last Olympian” (Percy Jackson, Book 5) where Percy and his fellow campers — all young teenagers — are waging war against the Titans of Greek myth, defending New York City, which, in the book, is the present site of Mount Olympus (confusing, I know, but you’ll understand when you read it). A typical 11-year-old might find the budding sexual tension between Percy and his closest friend, Annabeth, boring, the bloody battles awesome and the whole story of heroism and sacrifice a beguiling template for the possible future.

I have no idea what Cal thinks — does he recall, did he understand, the grounding in the Greek myths from the earlier books and our forays into the D’Aulaires’ classic “Book of Greek Myths”? What image does he conjure of Percy? Does Percy have a face? What do faces look like to Cal? Can his mind and body fathom running? I can’t know. What I hope is that my voice, at least — its steadiness, its continuous, faithful tracing of the words — conjures something meaningful.