When we think about vocabulary, it's tempting to focus on how many words a child knows. And yes, the number of words matters — but what matters even more is how well a child knows those words. A child who can name "dog" is off to a great start, but a child who can tell you a dog is an animal, that dogs bark, run, and fetch, and that some dogs are fluffy, big, or friendly — that child has vocabulary depth. And it's that depth that makes all the difference for language, learning, and literacy.
At Speaking Speech Pathology, we spend a lot of time working on vocabulary — not just teaching children new words, but helping them build rich, connected word knowledge. The children who use language most confidently aren't necessarily the ones with the biggest vocabularies. They're the ones who know their words deeply. In this article, we'll walk through three key areas of vocabulary development: categories, verbs, and describing words — and explain why each one matters.
What Do We Mean by Vocabulary Depth?
Think of vocabulary like a filing cabinet. A child might have a word in their cabinet, but if it's just sitting loose on a shelf with no connections, it's much harder to find and use. Vocabulary depth is about building connections — knowing what group a word belongs to, what it does, what it looks like, where you find it, and how it relates to other words.
Research tells us that children with deeper vocabulary knowledge have stronger reading comprehension, better academic outcomes, and more flexible language skills overall (Perfetti, 2007). This is one reason vocabulary sits at the heart of the language-comprehension side of the Simple View of Reading. In the classroom, children are expected to do much more than label pictures. The Australian Curriculum asks children to use precise vocabulary, classify and compare, and describe in detail from the very earliest years of school (ACARA, n.d.).
Categories: Why Classification Matters
Categorisation is one of the foundations of vocabulary. When a child learns that a banana is a fruit, and that fruit is a type of food, they're building a mental filing system that helps them store and retrieve words efficiently.
Category knowledge supports:
- Word learning: When a child has a strong sense of categories, they can slot new words into existing groups. Learning "kiwi fruit" is much easier if you already know what fruit is.
- Word retrieval: Children who organise words into categories can find and use them faster — if a child is trying to think of something to eat, having a mental "food" category to scan through is enormously helpful.
- Following instructions and reasoning: Classroom directions often rely on category knowledge ("put away the craft supplies"), and the same sorting-and-grouping thinking underpins maths, science, and literacy. (We unpack this further in our article on concepts and following directions.)
Children typically begin grouping things by basic categories (animals, food, clothes) around age 2–3, and develop more refined categories (farm animals vs. sea animals, summer clothes vs. winter clothes) through the preschool and early school years.
Verbs: The Engine Room of Language
If nouns are the bricks of a sentence, verbs are the engine. Verbs are what make sentences go — and research consistently shows that verb knowledge is one of the strongest predictors of overall language development in young children.
Hadley, Rispoli, and Holt (2017) found that the diversity of verbs a child uses at age two is a powerful predictor of later sentence complexity. Children who use a wider range of verbs tend to build more complex, grammatically sophisticated sentences earlier. This makes sense when you think about it: each new verb opens up a new sentence structure. "Push" lets you say "Push the car." "Want" lets you say "I want the car." "Give" lets you say "Give me the car." Each verb creates a different framework for expressing ideas.
Across many years working alongside teachers, I've found that verbs and describing words are the ones children miss most often, even when they sound like confident talkers. Despite this, verbs often receive less attention than nouns in everyday interactions with children. We're great at naming things — "Look, a bird!" — but we don't always highlight what things do or what we do with them. Yet for a child to move beyond simple labelling and start combining words and building sentences, they need a solid bank of verbs.
Types of Verbs to Build
- Action verbs: run, jump, push, throw, cut, pour
- State verbs: want, like, need, know, see, hear
- Mental verbs: think, remember, wonder, guess
As children move through primary school, the Australian Curriculum expectations shift towards verbs that describe processes, relationships, and thinking — verbs like "compare," "investigate," "predict," and "explain" (ACARA, n.d.). Building a strong verb vocabulary early sets children up for these later demands.
Describing Words: Adding Colour and Detail
Adjectives and adverbs — words that describe — are what turn basic sentences into rich, detailed communication. "The dog ran" becomes "The big, shaggy dog ran quickly down the steep hill." Describing words help children:
- Express themselves more precisely: Instead of "I want that one," a child can say "I want the blue one" or "I want the really big one."
- Understand and follow instructions: "Get the long pencil" or "Walk slowly" both rely on understanding describing words.
- Make sense of books and writing: Books are full of descriptive language, and children need these words to follow stories and — later on — to bring their own writing to life.
Developmental Progression
Children typically begin using basic adjectives (big, hot, yucky) around 18 months to 2 years. By 3–4 years, most children are using a range of size, colour, and texture words. More abstract descriptors — words like "heavy," "narrow," "gentle," or "ancient" — develop through the school years and benefit enormously from explicit teaching and rich language exposure.
Adverbs (quickly, carefully, loudly) tend to emerge a little later and are closely tied to verb knowledge. A child who knows a range of verbs is better positioned to start modifying them — you can't "tiptoe quietly" if you don't yet know "tiptoe."
How These Areas Work Together
Categories, verbs, and describing words don't develop in isolation. They're deeply interconnected. A child who can categorise "apple" as a fruit might also learn to describe it (red, crunchy, round) and talk about what you do with it (wash, peel, bite, slice). That web of connections is what makes vocabulary truly functional — it's what allows a child to talk about their world with precision, to understand what they read, and to express original ideas.
When vocabulary is limited or shallow, it can show up as:
- Difficulty finding the right word (word-finding challenges)
- Over-reliance on vague words like "thing," "stuff," or "that one"
- Trouble understanding classroom instructions
- Limited detail in storytelling or writing
- Difficulty with reading comprehension as texts become more complex
When Should You Be Concerned?
Every child develops vocabulary at their own pace, and there's a wide range of what's typical. However, if your child is consistently struggling to learn new words, has difficulty grouping or describing things, uses far fewer verbs than their peers, or seems to be falling behind with classroom language demands, it's worth having a chat with a speech pathologist.
At Speaking Speech Pathology, we assess vocabulary in a thorough, play-based way — looking not just at how many words your child knows, but at the depth and quality of their word knowledge. From there, we can build targeted, engaging therapy that strengthens exactly the areas your child needs.
Ready for practical strategies? Read our companion article: Activities to Build Vocabulary Depth in Children | Brisbane Speech Pathologist
Alexandra Bouwmeester is a Senior Speech Pathologist (MSPA, CPSP) and the founder of Speaking Speech Pathology, with over 14 years' experience supporting children's vocabulary and language. She offers mobile speech pathology to families across Brisbane's south side and Logan.
If you'd like to learn more about your child's vocabulary development, or you'd like to book an assessment, we'd love to hear from you. Get in touch with Speaking Speech Pathology today.
References
- ACARA (Australian Curriculum, Assessment and Reporting Authority). (n.d.). The Australian Curriculum: English.
- Hadley, P. A., Rispoli, M., & Holt, J. K. (2017). Input subject diversity accelerates the growth of tense and agreement: Indirect benefits from a parent-implemented intervention. Journal of Speech, Language, and Hearing Research, 60(9), 2619–2635.
- Perfetti, C. (2007). Reading ability: Lexical quality to comprehension. Scientific Studies of Reading, 11(4), 357–383.
