The reason for August’s inability to speak immediately after his jaw surgery is simple: his jaw was wired shut. The surgery had involved inserting part of his hip bone into his chin “to make it look more normal,” and August was in a lot of pain. Unfortunately, the surgery did not remove August’s need to chew food “in the front of [his] mouth.” This has led August to the opinion that he eats like a tortoise or a “prehistoric swamp thing.”
Due to August’s temporary inability to speak in the aftermath of the surgery, his mother came up with a “one to ten” system that August could use to show how much a particular wound was hurting. While one indicated low pain levels, ten indicated extreme pain. Having this information meant that his mother had useful information ready when the doctor did his rounds, regardless of the fact that Auggie cannot speak at the time.
The habit proves to stick long after Auggie recovers from his jaw surgery, and is regularly used to measure the pain caused by things like “a plain old sore throat.” After August’s first day at Beecher Prep, his mother uses the “one to ten” question to establish how his first day went, before launching into a barrage of questions about Summer, what his teachers were like, and how his classmates treated him.
On the topic of surgery, a humorous and memorable moment in the story (both the book and the film adaptation) occurs when Jack asks August if it is possible for him to get plastic surgery to improve his appearance. August replies that his current visage is the result of plastic surgery, and Jack suggests that he sue his doctor, which leads both of them to “[laugh] so much [they] couldn’t stop.”
August’s sister, Via, remembers the aftermath of August’s jaw surgery as an important time in her life as she went to stay with her grandmother and, for once, did not have to live in the shadow of August’s needs.
Via knows her brother to be “a trooper” about his medical issues. Her knowledge of his ability to bounce back after surgeries, such as the jaw surgery, leads her to be suspicious that something else is going on when he doesn’t want to go the Halloween Parade due to nausea.