How Can You Build Your Child's Vocabulary to Support Reading Comprehension?
When we think about why children struggle to understand what they read, we often focus on decoding—can they sound out the words? But comprehension is actually a two-part equation. Decoding is one piece. The other is language comprehension: the ability to understand the words, sentences, and ideas once the text is spoken or heard. And a critical factor in language comprehension is vocabulary.
Research is unambiguous on this point: vocabulary knowledge is one of the strongest predictors of reading comprehension. Children who know more words understand more of what they read—full stop. This is why two children can have similar decoding skills but very different levels of reading comprehension. The child with richer vocabulary encounters a text and understands it deeply. The child with more limited vocabulary hits unknown words like speed bumps, and the meaning of whole passages can collapse.
There are two kinds of vocabulary that matter for reading. Oral vocabulary is the bank of words a child knows and understands when they hear them spoken. Reading vocabulary is the bank of words a child knows when they encounter them in print. Oral vocabulary typically develops first and can be built through conversation, read-alouds, and rich discussion. Over time, through wide reading, a child's reading vocabulary grows as well—but this only works if the foundational oral vocabulary is strong enough to support comprehension of what they're reading.
Building vocabulary doesn't require flashcards or word lists (though those can have a place). The most powerful vocabulary building happens through: wide reading and being read to, especially with books slightly above a child's independent reading level; explicit discussion of interesting words encountered in books, TV, and conversation; developing word consciousness—a genuine curiosity and delight in words; and studying word parts (roots, prefixes, and suffixes), which can unlock the meaning of thousands of words at once. When a child knows that "rupt" means "break," words like disrupt, interrupt, rupture, and erupt all suddenly make sense.
If your child comprehends well when listening but struggles when reading independently, vocabulary may be part of the picture—but it's also worth exploring decoding and fluency. If they struggle to understand even when listening, vocabulary and background knowledge deserve more attention. I can help you figure out which piece of the puzzle needs the most support. Reach out at megan@mmcliteracycollective.com or (312) 315-2905.
