To grow up as the child of well-educated parents in an affluent American home is to hit the verbal lottery. From their earliest days, these children reap the benefits of parents who speak in complete sentences, engage them in rich dinner table conversation, and read them to sleep at bedtime. Verbal parents chatter incessantly, offering a running commentary on vegetable options in the produce aisle, pointing out letters and words in storefronts and street signs. Parents proceed, as Ginia Bellafante of the New York Times once put it, “in a near constant mode of annotation.”

In sharp contrast, early disadvantages in language among low-income children—both the low volume of words they hear and the way in which they are employed—establish a verbal inertia that is immensely difficult to address or reverse. Schools will spend every moment trying to make up for the verbal gaps kids come to school with on Day One, which usually grow wider year after year.

When it comes to vocabulary, size matters. E.D. Hirsch, Jr. observed that vocabulary “is a convenient proxy for a whole range of educational attainments and abilities.” It signals competence in reading and writing and correlates with SAT success—which, in turn, predicts the likelihood of college attendance, graduation, and the associated wage premium that has been fetishized by education reformers and driven their agenda for decades.

But vocabulary is important even for kids whose pathway to the middle class does not include college. Studies of the Armed Forces Qualification Test show that the test predicts job-performance and income gains most accurately when you double the verbal score and add it to the math score. In short, those old Reader’s Digest vocabulary quizzes had it exactly right. It really does pay to increase your word power.

What’s the best way to build vocabulary? If you went to college, there was probably a point during your junior or senior year of high school when you devoted many tedious hours to rote memorization of “SAT words.” Perhaps some of them found their way into your repertoire—assiduous, enervating, perfidious—and you use them to this day. However, the overwhelming majority of words you know and use were not learned through memorization, but by repeated exposure to unfamiliar words in context until they became part of your working vocabulary

Among educators, vocabulary is often described as “tiered.” Tier-one words include basic words that most native speakers come to school with regardless of upbringing: baby, dog, run, chair, happy. Tier three represents specialized vocabulary associated with specialized domains of knowledge and rarely heard elsewhere, such as isotope or exposition. The sweet spot for vocabulary growth and language proficiency are tier-two words, which occur in a variety of domains. Words like verify, superior, and negligent are common to sophisticated adult speech and reading; we perceive them as ordinary, not specialized language. Tier-two words are essential to reading comprehension and undergird more subtle and precise use of language, both receptive (reading, hearing) and expressive (writing, speaking).

Consider how a child might come to encounter the tier-two word “durable.” She would need multiple exposures to the word—not memorization. Here are some potential uses of the word “durable” she might encounter culled from children’s books, websites, and advertisements:

“The Egyptians learned how to make durable sheets of parchment from the papyrus plant.”

“With this lightweight and durable telescope, young scientists can explore the natural wonders of the earth or the craters of the moon and beyond.”

“Many durable ancient Roman concrete buildings are still in use after more than 2,000 years.”

“Instead of having to find caves or create makeshift shelters for protection from the weather, man started to look for more durable materials with which to build long-lasting dwellings”

In order for the vocabulary-building process to work, she must understand the gist of what she hears or reads and be able to contextualize the unfamiliar new word in each exposure. In the examples above, terms like “Egyptians,” “parchment,” “papyrus,” “makeshift shelters,” and “concrete” lend sense and meaning to the word “durable.” Without the enabling context, the word “durable” is one among many in the sentence or utterance she is unfamiliar with, and language growth stalls. This is the Matthew Effect in action: Those who have the broadest general knowledge, whether acquired at home, school, or elsewhere in their lives, are most likely to possess the “schema” necessary to intuit the meaning of the word in context and ultimately incorporate the new word into their vocabulary; those who do not fall further behind. The language-rich grow richer; the poor get poorer. 

Seen through this lens, it is immediately and abundantly clear that the key to language growth is the broadest possible knowledge base—the context-creating engine of language growth. And it proceeds from this that the best way to ensure language growth is a primary education that is as rich and varied as possible. In short, schools that hope to educate for upward mobility should be doing all they can to make children as rich as possible in knowledge and language—so that they can grow richer still. To be avoided at all costs is any impulse to narrow curriculum to an ill-conceived regimen of reading skills and strategies at the expense of a well-defined curriculum constructed around coherent, sequential, and rich domain-based content. Low-income children most specifically need more, science, social studies, art, and music to build the necessary “schema” that drive comprehension and language growth.

It goes firmly against the grain of current pedagogical fashion and political tradition, but regardless of where one attends school—for reasons of language development, skills development, and civic engagement—there should be far more similarities than differences in the content of K–8 education in America. The promise of preparing children for academic achievement and upward mobility depends upon a base level of language proficiency. Elementary and middle school education should set the stage for independent exploration. It should not be independent exploration. Insisting on hyper-local choice and encouraging wild variation in content within and across schools, districts, and states makes no more sense than insisting on a local alphabet.

To put the matter bluntly, language cares little about education homilies about child-centered schools and culturally relevant pedagogy. Language cares even less about local control of curriculum. There is a language of upward mobility in America. It has an expansive and nuanced vocabulary that it employs to nimbly navigate the world of organizations, institutions, and opportunities.

Without a common body of knowledge and its associated gains in vocabulary and language proficiency as a first purpose of American education, the achievement gap will remain a permanent fixture of American society, and the odds of upward mobility—already depressingly long—will become nearly insurmountable.

This essay was adapted from a longer paper released at the "Education for Upward Mobility"conference on December 2 and will be featured in a book to be released in 2015.