Vocabulary instruction: how to choose words and teach them so they stick

Why does vocabulary matter so much for reading?

A student can decode every word in a sentence and still not understand it if a few of those words are unfamiliar. Vocabulary and reading comprehension are closely linked, with studies across many countries finding strong correlations between the two. Once decoding is in place, vocabulary is often the thing that separates students who understand from students who don't.

The gap also grows over time. Students who know more words understand more of what they read, so they read more and learn more words. Students who know fewer words get less out of each page, read less, and fall further behind. Teaching vocabulary deliberately is one of the few ways to slow that spiral.

What are tier 1, tier 2 and tier 3 words?

Isabel Beck, Margaret McKeown and Linda Kucan sorted words into three tiers to help teachers decide what to teach. The tiers aren't a fixed list. They're a way of thinking about how useful a word is and where students are likely to meet it.

Tier 2 words give the most return for teaching time. They show up in stories, science, history and math, and students rarely pick them up from conversation alone. A student who learns "reluctant" will meet it in a novel, a news article and a history text, while "magma" mostly stays in earth science.

How do you choose which words to teach?

Start with the text you're about to read. List the words students might not know, then cross off the ones they can figure out easily and the ones that aren't worth the time. What's left is usually a short list of tier 2 words, plus any tier 3 words needed to understand the topic.

1. Is the word useful beyond this text? Prefer words students will meet again in many places.
2. Can students connect it to words or ideas they already know? "Fortunate" connects to "lucky", which makes it easy to teach.
3. Is it needed to understand this text? A key word for the main idea moves up the list.
4. Is it partly known? Words students have heard but can't explain are often the quickest wins.

Aim for about five to ten words a week for direct teaching. That sounds small, but taught well and revisited, it adds up to a few hundred words over a year, on top of everything students learn from reading and conversation.

What does robust vocabulary instruction look like?

In this kind of teaching, students do something with a word, rather than copying a dictionary definition. Students need to hear a clear explanation, see the word used in several ways, and use it themselves, across several days. A single exposure on Monday is forgotten by Friday.

1. Say the word and have students repeat it, so they have the sound in mind.
2. Give a student-friendly explanation in everyday language, not a dictionary definition.
3. Show the word in the sentence from the text, then in two or three other sentences.
4. Ask students to judge examples and non-examples of the word.
5. Have students use the word in a sentence about their own lives.
6. Return to the word over the next week in talk, writing and review games.

Why are dictionary definitions not enough?

Dictionary definitions are written for people who already know a lot of words. They're short, abstract, and often use words harder than the one being defined. A student who reads that "reluctant" means "unwilling and hesitant" has traded one unknown word for two.

Student-friendly explanations use plain words and describe the word in use. Instead of "unwilling and hesitant", say "if you're reluctant to do something, you don't really want to do it". Dictionaries still have a place, especially for older students, but they work best after students already have a sense of the word.

How does morphology help vocabulary?

Morphology is the study of meaningful word parts: prefixes, suffixes, bases and roots. Teaching these parts gives students a way to work out words they've never been taught. A student who knows that "pre" means before and "dict" relates to saying can make a strong guess at "predict", "dictate" and "prediction".

Nagy and Anderson estimated that printed school English contains tens of thousands of word families, far more than anyone could teach one at a time. Many of the unfamiliar words students meet in upper grades can be broken into known parts. That's why word-part teaching matters more each year from third grade on.

What role does wide reading play?

Most words people know were never taught to them. They were picked up from reading and conversation, a little at a time. Each time a student meets a word in context, they learn a bit more about it, although the chance of learning it from any single encounter is small.

That means volume matters. Students who read a lot meet many more words, and they meet them often enough to learn them. For younger students and weak decoders, read-alouds fill this role, because books contain far more rare words than everyday talk does.

How should vocabulary teaching change by grade?

In kindergarten through second grade, most vocabulary teaching happens through read-alouds and talk. Students can understand far harder words when they hear them than when they read them, so read-alouds are the main source of new words. Pick a few words from each book and teach them after reading.

From third grade on, students start meeting new words in their own reading. Direct teaching of tier 2 words continues, and morphology becomes a bigger part of the plan. By middle school, academic vocabulary across subjects is a large share of what students need, which is why the What Works Clearinghouse adolescent literacy guide lists explicit vocabulary instruction as its first recommendation.

How do you know vocabulary teaching is working?

Listen for the words in student talk and look for them in student writing. A word that's truly learned shows up on its own, without a prompt, in the right context. A word that only appears on a quiz hasn't really been learned.

Quick checks help too. Every few weeks, ask students to sort taught words into "I can explain it", "I know it a little" and "I don't know it". Reteach the words that keep landing in the last group, and drop the ones everyone knows.

How should English learners be supported?

English learners need everything above, plus attention to some words that native speakers already know. A tier 1 word like "bench" or "puddle" may be new to a student learning English, and it can block understanding of a whole passage. Check quickly which everyday words in a text might be unfamiliar, and give short explanations with pictures or gestures.

Cognates are a big help for students who speak Spanish, French, Portuguese or other languages with Latin roots. "Enormous" is "enorme" in Spanish, and "construct" is "construir". Pointing out cognates turns a student's first language into a resource. Watch out for false friends, though, like "embarrassed" and the Spanish "embarazada", which means pregnant.

What does a week of vocabulary teaching look like?

Here is a simple plan for a third grade class reading a short novel. On Monday, the teacher introduces five words from the next chapter with student-friendly explanations and a quick example for each. Students read the chapter, and the teacher pauses briefly at each word.

On Tuesday and Wednesday, students do short activities with the words: deciding whether examples fit, finishing sentences, and using the words in partner talk. On Thursday, one word part from the week gets a few minutes of attention. On Friday, students use at least two of the words in a short written response, and the teacher notes which words still need work the following week.

How do you review taught words without boring students?

Short games work well for review. Ask students to pick the better word for a sentence, to give a thumbs-up when a sentence uses a word correctly, or to connect two taught words in one sentence. Each takes a minute or two, and students enjoy the challenge.

Mix older words into these games so they don't fade. A word taught in September should still show up now and then in November, because one week of attention is rarely enough for a word to become part of a student's own speech and writing.

Common questions from teachers

Teachers often ask whether to give vocabulary tests. Short checks are useful, but a test that asks students to match words to definitions mostly measures memorization. Ask students to use the words, judge examples, or explain the difference between two related words instead.