Reading Mistake #15: Leaving Vocabulary to Chance

When we think about reading instruction, we often focus on phonics, decoding, and fluency. Those skills are essential, but they aren’t enough on their own. Students cannot fully understand a text if they don’t understand the words. One reading mistake to avoid this school year is assuming students will naturally acquire all the vocabulary they need simply by reading or hearing new words in context. While incidental learning does happen, research consistently shows that many words, especially academic vocabulary, require explicit instruction, and leaving vocabulary to chance isn’t best practice.

Not All Words Should Be Taught the Same Way

One of the most useful frameworks for vocabulary instruction comes from Isabel Beck, Margaret McKeown, and Linda Kucan in Bringing Words to Life. They organized vocabulary into three tiers, helping teachers decide which words deserve instructional time.

Tier 1: Everyday Words

Tier 1 words are the words children typically learn naturally through everyday conversation.

Examples include:

  • dog
  • happy
  • table
  • run
  • family

Most native English speakers acquire these words without direct instruction because they hear and use them frequently. However, some students, particularly multilingual learners or students with limited language exposure, may still benefit from explicit teaching of these words.

Tier 2: The Words That Deserve Your Attention

Tier 2 words are high-utility academic words that appear across many books and subject areas.

Examples include:

  • analyze
  • compare
  • predict
  • conclude
  • fortunate
  • determine

These words are less common in everyday conversation but appear repeatedly in classroom instruction and written text. Because students encounter them across multiple subjects, they provide one of the greatest returns on instructional time. This is why Beck and colleagues recommend making Tier 2 vocabulary a major focus of explicit instruction.

When introducing a Tier 2 word:

  • Explain it in student-friendly language.
  • Connect it to words students already know.
  • Use it in multiple sentences.
  • Revisit it often.
  • Encourage students to use it in speaking and writing.

Repeated, meaningful exposure helps move a word from short-term memory into a student’s everyday vocabulary.

Tier 3: Content-Specific Words

Tier 3 words are specialized words that belong to a particular subject or unit of study.

Examples include:

  • photosynthesis
  • denominator
  • evaporation
  • chromosome
  • peninsula

These words should be taught before or during a lesson because students need them to understand the new content. Once the unit ends, students may encounter them less frequently, but they’re critical for building background knowledge in that subject.

Choose Your Words Intentionally

One of the biggest shifts teachers can make is realizing that they don’t need to teach every unfamiliar word.

Instead, ask yourself:

  • Will students encounter this word again?
  • Does this word appear across multiple subjects?
  • Is understanding this word essential for comprehension?

If the answer is yes, it’s probably worth teaching explicitly.

Connect Vocabulary to Morphology

As students become stronger readers, vocabulary instruction becomes even more powerful when paired with morphology.

For example:

predict

  • pre- = before
  • dict = say

Students aren’t just memorizing a definition; they’re learning meaningful word parts they can apply to dozens of other words, such as dictionary, dictate, contradict, and prediction. This transforms vocabulary instruction from memorization into word learning.

The Bottom Line

Vocabulary doesn’t simply “happen.” Strong readers develop strong vocabularies because teachers intentionally introduce important words, explain them clearly, revisit them often, and help students use them in meaningful ways. The goal isn’t to teach every unfamiliar word. The goal is to teach the right words. When students understand the language, they can focus on the ideas. And that’s when comprehension truly begins.

References

  • Beck, I. L., McKeown, M. G., & Kucan, L. Bringing Words to Life: Robust Vocabulary Instruction (2nd ed.). Guilford Press, 2013.
  • Iowa Reading Research Center. The Importance of Word Choice in Explicit Vocabulary Instruction.
  • New South Wales Department of Education. Guide for Planning and Implementing Explicit Vocabulary Instruction.