Vocabulary: The Key to Comprehension

Part 5 of the Science of Reading Simplified Series

In part 5 of the Science of Reading Simplified blog series, we discuss why a student’s acquisition of words through a variety of settings and contexts will lead to better reading comprehension.

Savvas Insights Team

Why Is Vocabulary Instruction Critical to Comprehension?


Imagine that someone presents you with a Spanish text and asks you to read it aloud. You do so and manage to say all the words. However, because you don’t speak Spanish, you don’t don’t know what the words mean and, therefore, you can’t comprehend what you’ve read. The same challenge occurs for individuals who have underdeveloped vocabularies. This is why vocabulary instruction is a vital, but often neglected, component of a comprehensive reading program.

The Science of Reading Simplified“Vocabulary and word meaning are necessary features of understanding,” said Savvas author and literacy expert Sharon Vaughn. “That’s fundamentally what understanding is, knowing the meaning of the words and having enough background knowledge to be able to apply it to the text.”

Vocabulary proficiency and reading comprehension, according to Science of Reading research, directly influence each other. Since reading comprehension is the goal of reading, then vocabulary development needs to be an integral part of an overall literacy program.

“Encourage students to find collections of words like the way they would collect ‘gemstones.’”

Acquiring many words and their meanings not only helps with comprehending stories and nonfiction texts, but it also allows students to understand academic language across other content areas, like math, science, and social studies. Vocabulary development also helps with understanding language used during assessments and standardized tests. Teaching students to be “collectors of words” — a phrase Sharon uses to make word acquisition fun — and to be familiar with their meanings can have endless benefits to many areas of their academics, as well as their lives outside the classroom.

What Is Vocabulary and Why Is It Important in Learning to Read?

Vocabulary is a term that refers to the words we need to know in order to communicate. We need to build our vocabulary — our collection of words we know — to both understand ideas, as well as clearly relay ideas to others. Vocabulary is a fundamental part of the reading process because with every new word a student learns, the likelihood that they will understand what they read increases.

“Well before children enter the classroom, they start acquiring words and the meaning of words,” said Sharon. “We just have to keep expanding students’ access to words and we can do that in many different ways.”

teacher reading aloud to class

Teachers can expand students’ access to words by reading aloud texts that contain more mature vocabulary than students typically access through their own independent reading, or by intentionally planning opportunities for them to hear and use new vocabulary words in rich discussions.

Promoting vocabulary development is an essential feature for promoting comprehension and student learning. Every academic content area encompasses discipline-specific vocabulary that a student must understand to be successful in those academic disciplines, as well as school as a whole. In order for a student to be a proficient reader, they need to know the words that will help them obtain new knowledge and be able to communicate clearly with others.

“Vocabulary and word meaning are necessary features of understanding.”

A student’s vocabulary level in the early grades is also highly predictive of their reading, language development, and overall academic achievement across the grades. Students benefit when teachers are systematic and mindful about using and introducing academic vocabulary in their teaching and everyday routines to provide a foundation for rich vocabulary knowledge and continued vocabulary growth.

The Three Tiers of Vocabulary

There are many, many words out there but not all of them have equal importance when it comes to teaching vocabulary to students that will enhance their academic performance. So, when thinking about what words to use in instruction, as well as while assessing word knowledge, teachers can refer to what’s known as the Three Tiers of Vocabulary (Beck & McKeown, 1985).

The Three Tiers of Vocabulary diagram

A word’s complexity, meaning, and frequency of use determines in which of the three tiers it fits. Below is a breakdown of the tiers with word examples for each.

  • Tier 1: These words are the most basic, familiar words that are commonly used in everyday conversation. These words typically only have one meaning, and do not usually require direct instruction. Examples include: girl, sad, bed, book, bus, red.
  • Tier 2: This tier contains high-frequency words that can often have multiple meanings and academic vocabulary that is found across disciplines and content areas. These words aren’t typically encountered in everyday conversation but can often be found in written texts. These words usually need direct instruction and can indicate how a student is progressing in their academics. Examples include: examine, valuable, classify, function, masterpiece, right.
  • Tier 3: These words are often referred to as low-frequency words and they usually only occur within a specific subject area. For example, students learn the word isosceles when they’re taught about isosceles triangles in a geometry class, but that word wouldn’t typically be used outside of that subject area. Other examples include: photosynthesis, molecule, aorta, osmosis.

It would be most beneficial for teachers to focus instruction on tier 2 words because those words are more difficult to learn due to their multiple meanings, yet they occur frequently across content areas. Whereas tier 1 words are so commonly used everyday that students typically already know their meanings, and tier 3 words are very specific to certain content areas and may be better for content area teachers to include in their vocabulary instruction.

What Vocabulary Instruction Looks Like in the Classroom

Effective vocabulary instruction has come a long way since memorizing word lists and their accompanying definitions. These days, it’s about teaching students to be collectors of words by providing them access to a wide variety of words through texts and spoken language while giving them meanings and definitions. But it’s also about teaching students to be aware of and curious about the words around them.

teacher reading aloud to class

“Encourage students to find collections of words like the way they would collect ‘gemstones,’” said Sharon. “You become a word collector when you listen to words and try to find words you don’t know. When someone says a word, you wonder about that word and wonder about whether or not there’s another way to use that word. You become a word learner.”

The key to fluency practice is providing lots of opportunities for reading in many different settings, whether it be in small groups, whole class, partner, or independently. So, if the whole class is reading a particular passage, the teacher can model reading fluently and everyone can read that same passage together. Then, students can turn to a partner and read it to each other. And then they can read independently.

One powerful way to teach vocabulary in the early grades is through read-alouds with books that are a little bit above their grade level and will usually include new words that you can introduce to them and they can collect and explore. During read-alouds and other learning activities, elementary teachers make word learning engaging and fun by having students use new vocabulary in relevant and meaningful ways.

“The kind of rich and meaningful way in which we attack the acquisition of words can be taught to young children, and that can be a huge asset to them as they go through life,” said Sharon.

Put Vocabulary Into Practice!

Now that we’ve learned all about vocabulary and why it’s such an important part of learning to read, here are some activities, information, and suggestions for educators to consider while planning instruction.

  • For Teachers

    Tips for Teaching Vocabulary

    Practice vocabulary instruction as part of a well-rounded reading curriculum with these tips you can use in the classroom right away:

    • When introducing a new word, be sure to give its definition. It’s also important for students to hear words in context (e.g., “You were getting a little raucous in the cafeteria. Let’s work on being calm and tranquil.”). Only when students encounter new words in varied and meaningful contexts can they begin to understand and use them correctly.
    • Read aloud texts that contain more mature vocabulary than students are able to access through their own independent reading.
    • Intentionally plan opportunities for students to use and hear the vocabulary words repeatedly in rich discussions and in writing. Review previously taught target words throughout the school year, and collect words in a prominent place in the classroom, such as a word board or in a student’s vocabulary log so they can be easily accessed.
  • For Sharing with Families

    Fostering a Vocabulary-Rich Environment

    Vocabulary growth flourishes in a language-rich environment that provides students with multiple opportunities for hearing and using new and academic vocabulary words. Administrators can encourage a school culture that celebrates language by promoting a schoolwide emphasis on vocabulary learning, which can be powerful in creating an environment that celebrates the importance of learning new words. The practice of using new words and specific academic vocabulary becomes natural and fun for teachers and students.

    When organizing the reading instruction in your school that is effective and well-rounded, make sure vocabulary instruction is a prominent component. Students will be better equipped to understand what they read across the grades and content areas.

  • For Administrators

    Teachers can share these engaging activities with students’ families that will help extend learning beyond the classroom. Let parents and caregivers know that by helping their children expand their vocabulary, they will be giving them the skills they need to comprehend what they read. And when children are able to comprehend what they read, they are more engaged and they are better equipped to transition from learning to read to reading to learn.

    • Read with your child every day and point out new and interesting words you find in the text. Talk to your child about the new words you find together and tell them what they mean.
    • Have conversations with your child about their day at school. Introduce new vocabulary words to help them describe what they saw or did that day. For example, if your child tells you they learned about volcanoes. You can ask, “Are volcanoes gigantic?” Then, you can explain that gigantic is another word for big.
    • Encourage your child to be a word collector by recording new vocabulary words in a journal or on a board in their room.

About The Author

Sharon Vaughn, Ph.D.

Dr. Vaughn is the Manuel J. Justiz Endowed Chair in Education and executive director of The Meadows Center for Preventing Educational Risk at The University of Texas at Austin. She is currently the principal investigator or co-principal investigator on several research initiatives (Institute for Education Sciences, National Institute for Child Health and Human Development, and U.S. Department of Education) investigating effective interventions for students with reading difficulties and students who are English language learners.


  • Beck, Isabel & Mckeown, Margaret. (1985). Teaching Vocabulary: Making the Instruction Fit the Goal. Educational Perspectives. 23.