Blog Word quality vs. word quantity

Word quality vs. word quantity

by Research Team

Parents are a child’s first teachers. They teach them how to smile, how to laugh, how to put on their shoes and jacket, and further down the line how to say words and sentences. We as a society have tasked parents with the job of teaching their little ones the skill of oral communication. But do you ever wonder exactly which words a child learns to speak? Does it even matter which words they hear or how many?

The short answer to both:
Yes. It matters a lot.

The long answer:
Yes. It still matters a lot. In a landmark study done by researchers Betty Hart and Todd. R. Risley during the late 20th century, 42 families had one hour of their household interactions recorded every month in the hopes of understanding what it was in a child’s early experience that could account for the dramatic differences in the rate of vocabulary growth.1 This study was done over the course of 2 and a half years and collected over a thousand hours of audio to be studied and analyzed.

They called their findings “The Early Catastrophe”.

The families were broken into three socio-economic groups: professional, working-class, and welfare. The word count for each group was then parsed and analyzed and the results they found were very, very surprising. By 36 months, the amount of words that a child had in their vocabulary from the professional group was about 1,100 different words, while the amount of words in a child’s vocabulary from the welfare group was about 500 different words. This gap in vocabulary was matched by a gap in the quantity of words a child heard as well. From the professional group, a child would hear about 45 million words by the age of four, absolutely dwarfing the amount that the average child from the welfare group heard, which was about 13 million words by age four.1

graph of children's vocabulary across income groups

So what? Maybe that doesn’t mean anything. How much do children really have to say anyway?

Well, a lot would be an understatement. Not only does a reduced vocabulary hinder a child’s ability to express themselves, which then in turn hinders their ability to communicate their thoughts and feelings accurately. It dramatically hinders their ability to listen, and the size of a child’s vocabulary makes a huge difference in how they perceive and interact with the world as a whole.

So, this is a huge deal.

On the flip side, children with both a wider vocabulary and a better familiarity of that vocabulary are able to learn at an accelerated rate. Why? They need to spend less time thinking of the word and what the word means and can spend more time thinking about what the sentence means. This gives them even more time to grasp the concept of what the idea means and even the ability to think of their own ideas. So though we’re talking about words on the surface level, it has enormous implications for the higher-level intellectual capacity that children develop in their formative years.

So how do we get there? Should we just shout the word ‘bath’ at our child 100 times every day to hit 45 million words, or should we dust off our old SAT prep books and read off the vocab section at dinner time? In another study conducted by Meredith L. Rowe from the University of Maryland, Rowe states that “Specific measures of input quality relate to child vocabulary skill at different points in development, even with SES and quantity of input controlled”.2 This is important since it means that depending on the age of a child, their vocabulary needs differ to match the developmental stage they’re currently at. Here is a rough breakdown of the needs that correspond with those different ages.

  • 0-2 years: Quantity of words
  • 2-3 years: Diversity or sophistication of the vocabulary of the input
  • 3-4 years: Decontextualized language such as narrative and explanations

These are important details to know, as they can provide insightful ways to interact meaningfully with your child to make sure that their changing developmental needs are being met.2

Nonetheless, current technology is unable to autonomously track and categorize “sophisticated vocabulary” from “decontextualized narratives and explanations.” So what’s the best thing right now? Well, going back to the research study conducted by Hart and Risley, there is a significantly strong correlation between the volume of words spoken by parents/heard by children and the size of a child’s vocabulary.1 This is partially intuitive. The more talking that occurs, the more likely that new and different words get used. So when in doubt, just talk! The worst that’ll happen is you’ll make your kid smile.

About the Author

Research Team

The Starling Research Team is comprised of talented speech therapists, pediatricians, child development researchers, parents, and students from all over the world. If you share our passion for early education and a knack for turning hard research into engaging, relatable, enlightening stories, why not introduce yourself to us (with a few writing samples) via

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