By Dr. Natalie Fallert
Welcome back to my fourth installment on the Science of Reading from a secondary lens. For these last two pieces, I will be living in the language comprehension strand of Scarborough's Reading Rope with today’s focus on vocabulary and background knowledge.
Before we go any further, a reminder: the Science of Reading is grounded in decades of research about how the brain works—how it learns, processes, and applies knowledge. As you read, keep asking yourself how this strand fits into the brain’s workload during reading.
When Students Lack Words
One of the hardest conversations I have with high school students happens after reviewing an ACT practice test.
They expect to talk about strategies. Instead, I have to tell them something else:
They don’t know enough words.
I call this being “word poor”—students who simply haven’t had enough exposure to language in print. There is no quick fix. While I can offer guidance and point them toward meaningful reading, vocabulary growth at this stage depends largely on sustained exposure over time.
And the impact is significant. Limited vocabulary affects comprehension, slows reading, and prevents students from accessing grade-level text across disciplines.
Teachers cannot control how much students read outside of school. But we can control how we build vocabulary inside our classrooms.
Teach Vocabulary As Content, Not A Skill
We are all guilty of teaching students what to do when they encounter a new or unfamiliar word: use context clues, look it up, or break it apart. These should not be discarded, but based on research, this is not enough. Relying on these strategies can lead to faulty definitions or misunderstandings of words. Students need explicit, systematic vocabulary instruction paired with rich language experiences.
To better understand this, let’s take a quick look at the vocabulary development outlined in Iowa’s Comprehensive State Literacy Plan (CSLP). Of course, students begin building their vocabulary at birth, but I am going to start with middle elementary here.
Note: This is what science says a child can or should be able to do at these milestones.
Middle elementary - 2nd–3rd Grade
Here, a students’ vocabulary shifts toward more academic and domain-specific words, as they acquire words across subject areas and refine their understanding of figurative language. Independent reading is a key factor in vocabulary growth, but just as important are exposure to new words, explicit instruction, and opportunities to use them in speaking and writing.
Late elementary - 4th-6th Grade
Students' vocabulary becomes more sophisticated, “including abstract and academic words. They can analyze word relationships, understand multiple-meaning words, and use figurative language with greater ease” (Iowa). Explicit instruction in Greek and Latin roots helps them to decode unfamiliar words. Students are reading more complex texts and producing more structured writing that uses more precise language to convey ideas effectively. They also benefit from explicit teaching of high-utility academic vocabulary.
Adolescence and Beyond - Middle and High School
Vocabulary becomes more subject-specific as students “encounter more technical and discipline-based language in textbooks, literature, and research materials.” Students “refine their understanding of nuanced word meanings, register (formal vs. informal language), and connotations” and “develop metalinguistic awareness” (the ability to recognize and understand various features of language, such as rules, structures, and functions beyond its immediate meaning) (Iowa). Again, explicit instruction in word formation, etymology (origin of a word), and academic vocabulary is essential for vocabulary growth.
Across every stage, one pattern holds: vocabulary grows through explicit, intentional instruction paired with meaningful use. Students need direct exposure to new words, opportunities to use them, and repeated encounters in meaningful contexts.
What Can A Teacher Do?
Explicit instruction
Teach 1-2 words a day. Define it, connect it, and use it. It might be tempting to have a pre-selected list of words for each grade level, but this undermines the importance of relevancy and connection. Instead, consider the texts or content currently under study and choose words specifically from the text or related to the content. This helps students better understand the text/content at hand, allows them to use the word immediately in writing or discussion, and will be useful in the future.
Focus on Tier 2 words–those that:
When working with these words, use student-friendly definitions. If students are being asked to define the words on their own, consider the Oxford Learner’s Dictionary. Give students opportunities to actively practice with the word(s). Strategies like the Frayer Model or semantic mapping remain highly effective when used intentionally.
If you have done the math, explicit instruction will expose students to only 200-400 new words per year, which is not nearly enough to support strong vocabulary growth and the development of proficient readers. So this cannot be a teacher’s only approach.
Implicit instruction
Another way to introduce students to new vocabulary is to do so implicitly. While reading, a teacher can call out words and quickly define them. Ask students to underline and circle the word and write the definition in the text (or on a sticky note they can use on the page). If a text has a few words that may need to be defined for better understanding, calling them out in the moment works well. If the text is more complex or has a larger number of unfamiliar words, it might be better to do this before reading, so as not to disrupt the narrative of the text.
Prioritize words that:
Building vocabulary is interconnected with background knowledge. “It is well accepted that the chief cause of the achievement gap between socioeconomic groups is a language gap, and the relationship between language and the world knowledge to which language refers is extremely strong…knowledge of a subject is automatically accompanied by language use that represents that knowledge” (Hirsch, 2003).
Background Knowledge
I have always known that background knowledge matters when reading, but I did not fully understand how essential it is to comprehension until I began digging into this work.
Reading is not just about decoding words or applying strategies. It is about making meaning—and meaning depends on what you already know.
When students know very little about a topic, they tend to stay at the surface level. They can repeat information, but they struggle to analyze, interpret, or question it. But when students have a foundation of knowledge, something different happens: they think more deeply, make connections, and engage in more meaningful discussion.
As I explored this idea further, a few realizations stood out:
Knowledge is not built in isolation—it is built in connected networks.
Students don’t just accumulate random facts. The brain organizes knowledge into connected systems. The more connections students have, the easier it is to learn new information and make sense of what they read. This is why teaching topics in isolation is less effective than building coherent units of study around related ideas.
Comprehension depends on what the reader brings to the text.
Readers are constantly filling in gaps—often without realizing it. They supply unstated assumptions, make inferences, and connect ideas based on what they already know. As E.D. Hirsch explains, comprehension requires the reader to bring enough background knowledge to make the text coherent (2003).
Inferencing is not a strategy—it is a byproduct of knowledge.
We often teach inferencing as a skill, but in reality, the brain generates inferences automatically when it has the knowledge to do so. When students lack that knowledge, no amount of “strategy instruction” can compensate (Willingham, 2023).
Many elements of literature rely on background knowledge.
Allusions, irony, symbolism, and tone are not just textual features—they depend on what the reader knows. Without that knowledge, students may decode the words correctly but miss the meaning entirely.
Writing improves when students know more.
When students have knowledge of a topic, they are better able to organize their ideas, use precise language, and develop their thinking. When they don’t, writing becomes an exercise in guessing or generalizing. This raises an important question for educators: when a student struggles with writing, is it truly a writing issue—or is it a knowledge issue?
Vocabulary is a form of background knowledge.
Knowing the words associated with a topic makes it easier to understand and engage with that topic. A larger vocabulary allows students to focus less on figuring out individual words and more on analyzing ideas, evaluating arguments, and interpreting meaning.
What Can a Teacher Do?
Embed background.
Embed background knowledge strategically instead of overwhelming students with it upfront. Frontloading large amounts of information can feel efficient, but it often overwhelms students or lacks relevance in the moment. Instead, introduce knowledge when students need it—close to the point of reading or discussion.
Use conceptual vocabulary sorts
Use tools like conceptual vocabulary sorts to build both vocabulary and knowledge simultaneously. When students categorize, connect, and revisit words, they are building the networks that support comprehension.
Keep it focused and purposeful.
Not everything needs to be taught. Prioritize the knowledge that will have the greatest impact on understanding the text or concept. This might include a short video, an image, or a brief explanation. For example, when introducing a Shakespearean play, students do not need an extensive lesson on the Globe Theatre or Shakespeare’s personal life before they begin reading. Instead, focus on the aspects of the time period that directly impact comprehension of the play.
A Final Thought
If there is one takeaway from this work, it’s this: comprehension is not built through strategies alone. It is built through words and knowledge—accumulated slowly, intentionally, and over time.
As secondary educators, we are not just teaching content; we are building the language and knowledge students need to access that content. Every word we teach, every connection we help students make, and every opportunity we create to engage with meaningful text contribute to that growth.
We may not be able to control how much students read outside our classrooms, but we can control the clarity, intention, and consistency of the language we build within them. And that work matters more than any single strategy we could teach.
Join me in my final post as I unpack print awareness and comprehension, and what they demand of us as secondary educators working to build skilled, confident readers.
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