Distinctive, curiously formal
The View from Saturday doesn't start us off easy.
The fact was that Mrs. Olinski did not know how she had chosen her team, and the further fact was that she didn't know that she didn't know until she did know. Of course, that is true of most things: You do not know up to and including the very last second before you do. And for Mrs. Olinski that was not until Bowl Day was over and so was the work of her four sixth graders. (1.2)
Whew. This isn't intimate and casual writing; we're not being drawn in to a cozy voice or hearing a lot of slang. For one thing, there aren't many contractions. Sure, we get "didn't" twice here, but for the most part characters don't talk with contractions. In fact, they don't talk much like sixth graders are all, as for example Julian's greeting to Mrs. Olinski: "We have not yet poured your tea, Mrs. Olinski. We did not want it to get cold" (8.18).
Sure, Julian might be an exception because he's had a fancy boarding school education. But notice that even Ethan worries that Julian's language might be "catchy" ("Ethan".33)—right after saying the word "indeed" for what might be the very first time in his life. Relying less on contractions, and more on words like "welcome" (8.16) and "indeed" makes things more formal, more polite, and more grown-up.
Perfect, in fact, for the characters' weekly ritual of afternoon tea.
Look at that first quotation again—the "didn't know that she didn't know"—and notice also that Konigsburg writes with complex, repetitive syntax (that is, the arrangements of words), using colons and conjunctions to create long sentences that are full of variety and distinction.
These sentences are also full of meaning. This narrator isn't trying to rush us through the plot; she's trying to make us slow down. You really have to linger over phrases like "she didn't know that she didn't know until she did know" to make sure you know exactly what's going on. You have to, in other words, "make each mile a journey of quarter inches" (10.5).