On Thursday night, Americans will turn on their televisions to watch the Scripps National Spelling Bee, where young students spell real words with real meanings that real people have never heard of before. Last year’s winning words, when two contestants tied for first, were feuilleton (a feature section in a European newspaper) and stichomythia (dialogue in alternating lines during a dispute).

Those words, 10- and 12-letter words respectively, look big and scary. But at this level, it’s the words with first-grade length that...