One of the most persistent myths about word acquisition is that students don't need to be taught words; they just need to read more and their vocabularies will magically expand. This theory — which I like to call "learning words by osmosis" — doesn't hold much promise for your average or struggling reader. While it may hold true for a select group of students who are strong, avid readers possessing a curiosity about words, most students don't learn words by simply encountering them in reading.

Don't get me wrong. There is a strong, positive correlation between amount of reading and vocabulary size. And, of course, getting students to read more is a worthy goal in and of itself for students. However, teachers cannot assume that students are learning unfamiliar vocabulary words in the course of their reading, and they therefore have a responsibility to ensure that all students gain vocabulary knowledge, not just "the readers" of the class.

What the Research Says

In terms of learning new words in the course of reading, research shows that does occur, but in small increments. That is, by no means will all the unfamiliar words encountered in reading be learned, and those that are learned will require multiple encounters with them before learning is accomplished. Studies estimate that of 100 unfamiliar words met in reading, between 5 and 15 of them will be learned (Nagy, Herman, & Anderson, 1985; Swanborn & de Glopper, 1999).
Bringing Words to Life (Beck at al., 2002)

Why are students only picking up 5-15% of the unfamiliar words they are encountering? One reason is that most writers are not using words to "teach words" but rather to tell a story or to make a point. Authors do not usually and intentionally seed their works with contextual clues to lead their readers to infer the meanings of words, nor should they; that would make for stilted and inauthentic writing. For example, read this climactic scene in Jane Eyre — when, after years of painful separation, Jane returns to her true love Rochester, who has been crippled and blinded by a fire. As you read, identify any vocabulary words that might stump young readers and consider any contextual clues that could help readers infer their meanings.

[Rochester] put out his hand with a quick gesture, but not seeing where I stood, he did not touch me. "Who is this? Who is this?" he demanded, trying, as it seemed, to see with those sightless eyes—unavailing and distressing attempt! "Answer me—speak again!" he ordered, imperiously and aloud.
"Will you have a little more water, sir? I spilt half of what was in the glass," I said.
"Who is it? What is it? Who speaks?"
"Pilot knows me, and John and Mary know I am here. I came only this evening," I answered.
"Great God!—what delusion has come over me? What sweet madness has seized me?"
"No delusion—no madness: your mind, sir, is too strong for delusion, your health too sound for frenzy."
"And where is the speaker? Is it only a voice? Oh! I cannot see, but I must feel, or my heart will stop and my brain burst. Whatever—whoever you are—be perceptible to the touch or I cannot live!"
He groped; I arrested his wandering hand, and prisoned it in both mine.
"Her very fingers!" he cried; "her small, slight fingers! If so there must be more of her."
The muscular hand broke from my custody; my arm was seized, my shoulder—neck—waist—I was entwined and gathered to him.
"Is it Jane? What is it? This is her shape—this is her size—"
"And this her voice," I added. "She is all here: her heart, too. God bless you, sir! I am glad to be so near you again."
Jane Eyre (Bronte, 1847)

If you are a student who has made it to page 400-something in Jane Eyre, are you pausing to consider the meaning of imperiously in this scene? Has Charlotte Bronte provided you with the context clues to figure it out? Was Charlotte Bronte even thinking about context clues as she wrote? Of course not. Bronte was not writing sentence completion questions for the SAT; she was writing a love story, and using the words that came naturally to her to convey that story.

As a reader, if you were to revisit the sentence "'Answer me—speak again!' he ordered, imperiously and aloud," you might be able to infer the meaning of imperiously as "in a commanding manner," but you could also inaccurately conclude the word as meaning "desperately" or "in a pleading manner." All three meanings would make sense in the context. But more to the point, as a reader, are you even thinking about the meaning of imperiously in this scene? Or, are you so swept up in the moment of Jane and Rochester's reunion that you are oblivious to the unfamiliar words you are encountering?

When it comes to literature, most readers tend to be plot-driven. If you are truly riveted by a story, do you really want to pause to interrupt the ride to look up a word? Fiction fans are usually reading to find out what happens next. They might not even consciously realize that they have encountered unfamiliar words in the story. That would be a small crack in the sidewalk, not disturbing them on their path to discover if Harry Potter will ultimately conquer Voldemort or if Atticus Finch will win his case.

As a point of contrast, read the following excerpt from the children's story Charlotte's Web:

"Are you awake, Charlotte?" [Wilbur] said softly.
"Yes," came the answer.
"What is that nifty little thing? Did you make it?"
"I did indeed," replied Charlotte in a weak voice.
"Is it a plaything?"
"Plaything? I should say not. It is my egg sac, my magnum opus."
"I don't know what a magnum opus is," said Wilbur.
"That's Latin," explained Charlotte. "It means 'great work.' This egg sac is my great work—the finest thing I have ever made."
Charlotte's Web (E.B. White, 1952)

E.B. White goes well beyond providing contextual clues for the meaning of magnum opus; he has woven in its definition through the dialogue between Wilbur and Charlotte. A young reader exposed to this scene may remember the meaning of magnum opus after this one exposure, but chances are still unlikely. If you poll the second grade class who is exposed to this scene the day after hearing it in a class read-aloud, the term may be familiar. If you ask the students what it means, one or two students may respond "an egg sac." If the teacher, while collecting students' homework the next morning, had referred to Billy's short story as a magnum opus, students would have an even better chance of recalling the term and may generalize its meaning to "any great work" instead of only associating it with Charlotte's egg sac.

The Rich Get Richer and the Poor Get Poorer

Returning to the excerpt from Beck's Bringing Words to Life, the incremental nature of vocabulary growth is reliant on multiple exposures to a single word. Wide readers will receive those multiple exposures through the many texts they encounter. And, some of those readers are lucky enough to be surrounded by friends, family members and teachers who act as "word mentors" and use those same words in their daily conversations. Strong readers also commonly possess the reading skills to figure out a word's meaning from context, if those contextual clues exist.

Struggling readers, on the other hand, tend not to challenge themselves with complex readings, have trouble making sense of contextual clues, and may not be surrounded by "word mentors" who use academic vocabulary in their daily lives. As a result, these students can't catch up in the word acquisition race without interventions.

The Teacher's Role

It's not realistic to expect that teachers can single-handedly compensate for students' lack of exposure to vocabulary from wide reading and oral reinforcement, but teachers can institute certain practices to help struggling readers experience multiple encounters with words and to become more word-conscious.

Previewing the vocabulary of a particular text before reading is commonly thought of as an ELL practice, but all students can benefit from being exposed to a group of words in isolation before reading them in context. Previewing a vocabulary word does not interrupt the reading process and students may experience a heightened awareness of the word and its meaning when they encounter it in the context of the reading. Previewing vocabulary does not necessarily have to take up valuable class time either. In a blended learning format, teachers can send students to Vocabulary.com via their computers or mobile devices to preview vocabulary by assigning lists based on popular works of literature, founding documents, speeches, or news articles.

Even though students may skip over—consciously or subconsciously—unfamiliar words in their reading, teachers can revisit pivotal passages in class and model word inference strategies that can expose students to the "habits of mind" most helpful for word learning. For example, students could be asked to highlight contextual clues present in the Jane Eyre passage that they most likely overlooked during their initial reading, such as demanded and ordered that are consistent with the meaning of imperiously. This exercise could also be extended to a discussion of characterization, since Rochester is consistently seen as having an imperious manner throughout Jane Eyre, even during his crippled state at the end of the novel.

As esteemed vocabulary instruction researcher Michael Graves candidly puts it, "You might as well not teach a word if you're not going to bother to review it." Because research has shown that students usually require between 10 and 16 encounters with a word before they learn it, it is necessary to have a systematic mode of vocabulary review. Just as Vocabulary.com can help students preview words before reading, it can also help students to review words after reading. Once a word has entered a student's learning program, it will periodically reappear based on the students' performance history of answering questions about that word in multiple contexts.

National Louis University professor Camille Blachowicz uses the analogy of the dimmer switch on a light to illustrate the incremental process of learning a word. The dimmer switch may start to move when a reader first encounters a word in the course of reading, but it can take multiple encounters in multiple contexts — oral or written — before the "light" goes on and the reader is able to use it with precision and accuracy. With this in mind, teachers can play a vital role in making sure that the light keeps getting brighter.