Do Prefixes, Suffixes, and Roots Help Kids Learn New Words?

Why do word parts matter for vocabulary?

Many of the long words your child will meet are built from smaller pieces. Researchers call the study of those pieces morphology, and you use it without thinking. If you know happy and you know un-, nobody has to explain unhappy.

Researchers William Nagy and Richard Anderson estimated in 1984 that about 60% of the unfamiliar words students in grades 3 to 9 meet in their reading can be worked out from smaller parts. That estimate is decades old, so treat it as a rough size, not an exact count. Still, it shows how much of a child's reading this skill can touch.

In a 2007 study of 111 fourth and fifth graders in California, most of them Spanish-speaking English learners, children who were better at finding the simpler word inside a longer one (popular inside popularity) also tended to have larger vocabularies and stronger reading comprehension. That shows a link, not proof of cause. The authors suggest word parts and vocabulary probably build on each other.

Does teaching word parts work?

For vocabulary and spelling, the research mostly says yes. A 2013 meta-analysis of 30 studies of school-age children found what its authors called moderate gains in vocabulary and spelling for children taught about word parts. The gains were bigger for younger students, and bigger on tests the researchers designed than on standardized tests.

A 2010 review of 22 studies, from preschool through grade 8, also found benefits, especially when word parts were taught alongside other literacy skills. A separate 2010 review of children with literacy difficulties found gains in vocabulary and spelling too.

The newest review is more cautious, and it's worth knowing why. A 2024 meta-analysis of 28 studies of primary school children found small to moderate effects on reading and spelling, with the biggest gains on the words children were directly taught. There was some evidence that spelling gains carried over to new words. But the authors rated the certainty of most of the evidence as low, few studies checked whether the gains lasted, and word part teaching wasn't clearly better than other language-focused teaching. That review measured reading and spelling, not vocabulary.

Will learning word parts improve reading comprehension?

Don't count on it by itself. Both the 2013 and the 2024 reviews found no clear effect on reading comprehension, even though better word part skills and stronger comprehension tend to go together.

A 2003 classroom study of 157 fifth graders shows the tradeoff. Some classes learned to use word parts and context clues, while others were taught the specific vocabulary in their social studies textbook. The word part group was better at working out the meaning of new words with prefixes and suffixes. The textbook group was better at learning the textbook's words. On comprehension, the two groups did not differ.

So word parts give your child a tool for words they haven't met yet, and teaching a specific word gives them that word. They do different jobs. Our post on which vocabulary words to practice covers the second job.

Which prefixes, suffixes, and roots should my child learn first?

Start with common prefixes, because a short list does a lot of the work. A 1989 analysis by White, Sowell, and Yanagihara found that 20 prefixes account for almost 97% of the prefixed words that show up most often in school reading. The top four make up about 58%:

• un- (not): unhappy, unfair
• re- (again): rebuild, rewrite
• in-, im-, il-, ir- (not): inactive, impossible, illegal, irregular
• dis- (not, opposite of): disagree, disappear

Next, add a few suffixes that change meaning in a way kids can see, like -er (one who, as in teacher), -less (without, as in hopeless), and -ful (full of, as in helpful). Reading Rockets has free charts of common prefixes, suffixes, and roots you can print.

Greek and Latin roots, like port (carry) in transportation or spect (look) in spectator, are harder because many of them can't stand alone as words. In a small 2016 study of 59 sixth and seventh graders, students taught Latin roots were better at using them to work out unfamiliar words. We'd save roots for upper elementary and middle school, but that is our judgment, not a tested rule. The authors of the 2007 study advise teaching roots when they come up in what a child is reading, not as a list to memorize.

Can word parts mislead my child?

Yes, so teach your child to check. Literacy experts Douglas Fisher and Nancy Frey write plainly that "word parts don't always work," and they advise showing examples where they fail. Uncle has no un- in it. Reason has nothing to do with doing something again. Invaluable means extremely valuable, not worthless.

Middle schoolers in the 2016 study made a related mistake: some assumed a word meant the same thing as its root, which nearly always led to a wrong guess. A root is a hint about meaning, not the definition.

A word part also only helps if your child knows the simpler word. The authors of the 2007 study point out that spotting fury inside furious is no use until a child knows what fury means. Words that change sound and spelling, like strength and strong, were among the hardest for children in that study, so it helps to point those out.

What can I do at home?

You don't need a program for this. Use the words your child is already reading, and keep it to a few minutes at a time.

• Stop at real words. When a long word shows up in a book or on a school list, look inside it together before reaching for a dictionary.
• Use four steps. The 2007 study's authors suggest this routine: notice you don't know the word, look for parts you do know, guess the meaning, then check the guess against the sentence.
• Build a word family. Pick one part and collect words that share it: portable, transport, import, export. Ask your child what the words have in common.
• Use families to explain odd spellings. Sign has a silent g, but you can hear it in signal and signature. Seeing the family makes the strange letter make sense.
• Hunt for fakes. Make a game of spotting words that only look like they have a prefix, like uncle and reason.
• Go slowly. We suggest one or two word parts a week, so each gets real use. Kids don't need to memorize a chart.

If your child keeps struggling to read or spell longer words, mention it to their teacher. Older reviews found word part teaching especially helpful for struggling readers, though the 2024 review did not find clear evidence of an extra benefit, so a teacher or specialist is the right person to judge what fits your child.

How does StudySpell fit into this?

How StudySpell helps: StudySpell doesn't teach prefixes, suffixes, or roots, and it won't break words apart for your child. That part is yours. What it can do is give a word family more practice once you've picked one.

Type a family into a word list, like portable, transport, import, and export. Each word is read aloud, your child types it from memory, and they find out right away whether they got it, with color-coded highlighting that shows where they slipped. A free account saves up to 3 lists of up to 7 words each, so one family fits easily.

For meanings, StudySpell Pro includes vocabulary practice built from your own list. If a word comes without a definition, we suggest one for you to review. Your child then matches each word to its meaning, chooses the right meaning from a set of options, or types the word from its definition (Pro). Talking about why the words belong together still happens with you.

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