Beginning with the first sentence of Infinite Jest, Wallace is outlining some of its core themes: Detachment, disembodiment, depersonalization, all resulting in disorientation -- a possible source, if I may borrow my LT friend, zenomax's, idea -- of the "realities behind the realities" in Infinite Jest.
"Normal," what for most of us is autonomic behavior in a meeting: appearing pleasant w/an approachable demeanor, appropriately crossing our legs and arms, making eye contact, following the give-and-take of a conversations natural cues, aren't automatic responses at all for Hal. The communication and appearance problem of Hal's, in fact, is so obvious to staff at E.T.A. that he's been coached on how to "appear normal" for this important meeting, and w/not very successful results. Because just his silence is abnormal and increasingly awkward-in-the-extreme, in an admissions meeting when Hal himself (and not his surrogate-mouthpiece-coach, C.T.) is supposed to be selling himself w/his own voice, showcasing his strengths and spotlighting why he should be selected for admission into the university. It's an interview, Hal! The idea is to talk, right?
But Hal is so far gone, he can't talk intellligibly, he's essentially attempting to act like a human being participating in a university admissions meeting, rather than just being a human being ... being himself. But who is he? Who is Hal? Does he even know? How can he when he's become disembodied from himself, disconnected from the reality of his circumstances? He thinks he knows what he isn't, as he'll protest later in the chapter that "I am not a machine," but he has more in common at this lowest point in his life with a machine; with his namesake 9000 series computer of 2001: A Space Odyssey infamy, for that matter, than he does with just being ... just being Hal (whoever that is), the human being.
Hal is most assuredly a veritable machine at this point in the novel, and just as computers aren't always programmed for every possible contingency in a crisis, so neither has Hal been coached/programmed thoroughly enough to survive this fateful, forever life-altering, crisis.
Hal had contradicted himself a year earlier, Nov. 3rd, Y.D.A.U., regarding his not being a machine, in one of his Big Buddy sessions (pp. 117-118), where he mentored pre-teen students on life and tennis at E.T.A., selling his younger cohorts on the idea that the tennis drills and repetitions of E.T.A. life are vitally necessary so that your muscle's movements "sink and soak" into your "hardware, the C.P.S. The Machine language ... The Machine language of muscles" (boldness again mine). What he's describing is a body and mind becoming so conditioned to stimuli (the 3-D dynamics of tennis) that thought-reactions cease, replaced by autonomic responses, much as a computer is programmed by endless repetitive data in order to "react" to input.
In the essay Wallace wrote on Tracy Austin's autobiography, I believe it's titled "How Tracy Austin Broke My Heart," he related how disappointed he was by her (whom he'd once had a teenage crush on, and I'm paraphrasing from memory, something to the effect of) "banal analytical" ability. She wrote in cliches and surface insights, and Wallace, expecting more from her, theorized her lack of depth was because the 100% of her body and mind that she had to exert 24/7 into tennis since she was a youngster, learning to turn her mind and muscle's movements into freed-of-thought, autonomic reactions, had drastically reduced, if not entirely eliminated, her ability to think or analyze except inside the rectilinear confines of the tennis court and its practiced cliches -- in that context of drills and repetitions. Wallace lamented that it was as if Tracy Austin's ability to critically think outside of the narrow focus of tennis did not exist for her, and could not because of her early formative years of hyper-conditioning. Which is the same kind of conditioning Hal and his fellow inmate-students underwent.