the father's delusion that his son is mute

The scene's engine, stated by the fluent boy it happens to: his father is convinced Hal cannot speak, and suffers a recurring delusion of "people's mouths moving but nothing coming out." Hal talks without pause for five pages, defines implore from the O.E.D., needles the disguise, and none of it registers as speech to the one man who most needs to hear it. The father's private hallucination is the whole book's public condition, and it is aimed straight at his own child.