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What words should your child learn at each age? A research-backed vocabulary roadmap

A practical companion to How the first years of listening shape a child's entire future — the concrete word lists behind our phase vocabulary bands.

Parents who read the research on early language development usually come away with the same conviction: what my child hears matters more than I realised. But the natural next question — which words, specifically, should my child know?— tends to go unanswered. Most parenting advice stops at “read more, talk more.”

That is a shame, because linguistics actually has an answer. Over the last century, researchers have built word-frequency lists that identify, with remarkable precision, the vocabulary that does the heaviest lifting in a child's language development. Three of these lists are public-domain, well-validated, and stack on top of each other cleanly from toddlerhood through the end of primary school.

This article walks through all three, and shows how they map onto the four developmental phases we use at Sonacast to generate children's audio content.

Why vocabulary is the lever

Vocabulary at age three is one of the strongest single predictors of later academic outcomes — stronger than parental income, stronger than screen-time habits, stronger than almost anything else that gets measured. The mechanism is compounding: children with larger vocabularies understand more of what they hear, which means they learn more from every subsequent conversation, story, and book.

Research summarised by Starglow Media found that children who listen to audiobooks are exposed to 40% more advanced vocabulary than children who only read the same books independently. Listening to or reading five books a day can expose a child to roughly 1.5 million more words by age five than children without that exposure.

The question is not whether vocabulary matters — it is which words deliver the most developmental value at each stage. That is exactly what the three frameworks below answer.

The three research layers

Three well-established, public-domain English word lists stack cleanly across childhood. Each was built by a different researcher, for a different purpose, but together they form a coherent progression.

Layer 1 — the Dolch list (ages 1–3).Compiled by Edward William Dolch in 1936 from children's books of the era, the Dolch “sight words” are the ~220 words that account for roughly half of all text children encounter in early reading. The first two subsets — Pre-Primer and Primer — contain about 90 words and are the natural target for the earliest years.

Layer 2 — the Fry 1000 (ages 3–7). Developed by Edward Fry in the 1950s and refined through the 1980s, the Fry list ranks the 1000 most frequent words in English texts. The first 300 alone account for roughly 65% of all written English; the full 1000 cover around 90%.

Layer 3 — the Academic Word List (ages 5–11). Published by Averil Coxhead in 2000, the AWL identifies 570 word families that appear with high frequency in academic writing across every discipline — but rarely in everyday conversation. This is the vocabulary gap that separates children who thrive in school from those who struggle. Most of it is learned, or not learned, between ages five and eleven.

The rest of this article walks through each layer and the specific Sonacast phase it maps to.

Phase 1 (ages 1–3): the Dolch foundation

The Dolch Pre-Primer and Primer lists together contain 92 words. They are dominated by function words (the, and, to, of), basic verbs (go, see, run, play), pronouns (I, you, we, they), and a handful of colours and numbers. They are called “sight words” because fluent readers recognise them instantly, without phonetic decoding — and the first step toward that fluency is simply hearing them, repeatedly, in natural context.

At ages 1–3, the most critical window for language acquisition, the goal is not breadth but repetition. A peer-reviewed study found that two-year-olds learn new words most reliably when those words appear in blocks of successive sentences rather than scattered across varied contexts. The Dolch words are the ones worth repeating that way.

Dolch Pre-Primer (40 words)

  • a
  • and
  • away
  • big
  • blue
  • can
  • come
  • down
  • find
  • for
  • funny
  • go
  • help
  • here
  • I
  • in
  • is
  • it
  • jump
  • little
  • look
  • make
  • me
  • my
  • not
  • one
  • play
  • red
  • run
  • said
  • see
  • the
  • three
  • to
  • two
  • up
  • we
  • where
  • yellow
  • you

Dolch Primer (52 words)

  • all
  • am
  • are
  • at
  • ate
  • be
  • black
  • brown
  • but
  • came
  • did
  • do
  • eat
  • four
  • get
  • good
  • have
  • he
  • into
  • like
  • must
  • new
  • no
  • now
  • on
  • our
  • out
  • please
  • pretty
  • ran
  • ride
  • saw
  • say
  • she
  • so
  • soon
  • that
  • there
  • they
  • this
  • too
  • under
  • want
  • was
  • well
  • went
  • what
  • white
  • who
  • will
  • with
  • yes

The full Dolch list is in the public domain and available from many sources, including the Dolch word list Wikipedia entry.

At Sonacast, Phase 1 (Foundation, ages 1–3) stories are constrained to the top-500 vocabulary band, which includes the full Dolch Pre-Primer and Primer lists plus the most frequent concrete nouns from child-directed speech corpora. Sentences stay between three and eight words, and new words are repeated in successive sentences — exactly as the research prescribes.

Phase 2 (ages 3–5): the Fry 300

Between ages three and five, a child's vocabulary can grow from a few hundred words to several thousand — a pace of acquisition that will never be matched again. The natural target for this phase is the first 300 words of the Fry list, which extend the Dolch foundation into a richer repertoire of action verbs, descriptive adjectives, and common content nouns.

The first 300 Fry words account for roughly two-thirds of all written English. A child who hears them repeatedly, in varied narrative contexts, arrives at kindergarten already fluent in the structural machinery of the language.

A representative sample from the Fry 300

  • about
  • after
  • again
  • another
  • because
  • before
  • boy
  • country
  • each
  • every
  • found
  • give
  • great
  • house
  • know
  • many
  • more
  • never
  • number
  • people
  • place
  • think
  • through
  • water
  • world

The complete Fry 1000 is public domain and freely available — a commonly cited version is the k12reader PDF set, which organises the list in blocks of 100.

At Sonacast, Phase 2 (Story explorer, ages 3–5) stories use the top-1500 vocabulary band — roughly the Fry 300 plus the next tier of high-frequency content words. Each story introduces two or three new words used three times in context, matching the repetition pattern the research identifies as optimal at this age.

Phase 3 (ages 5–7): the full Fry 1000

By age five, a child is ready for the full Fry 1000 — the complete high-frequency vocabulary of written English. This is also the stage at which listening comprehension begins to outpace reading comprehension: a child can understand, via audio, vocabulary they cannot yet decode on the page. That gap is where audio does its most valuable work.

The second half of the Fry 1000 introduces abstract nouns, descriptive verbs, and the connective vocabulary that structures real narrative thought.

A representative sample from the full Fry 1000

  • against
  • believe
  • century
  • common
  • complete
  • covered
  • decided
  • difference
  • discovered
  • explain
  • language
  • listen
  • material
  • measure
  • natural
  • pattern
  • probably
  • produce
  • remember
  • rhythm
  • simple
  • statement
  • surface
  • temperature
  • understand

At Sonacast, Phase 3 (Story builder, ages 5–7) stories use the top-3000 vocabulary band — the full Fry 1000 plus a wider shell of narrative vocabulary. Stories become longer (8–15 minutes), hold multiple characters, and can carry abstract ideas that reading alone would still be out of reach for a child of this age.

Phase 4 (ages 7–9): the Academic Word List

This is where the research gets interesting — and where the developmental gap between children really opens up. The Academic Word List (AWL), developed by Averil Coxhead at Victoria University of Wellington, identifies 570 word families that appear frequently in academic writing across every discipline, from history to biology to mathematics.

Crucially, these are words that rarely appear in everyday conversation. A child who does not encounter them in books, audiobooks, or rich narrative content simply will not acquire them. This is the vocabulary gap that shows up in reading-comprehension gaps by age eleven, and in the confidence gap between children who thrive in secondary school and those who find it bewildering.

A representative sample from the Academic Word List

  • analyse
  • approach
  • concept
  • consist
  • constitute
  • context
  • define
  • derive
  • establish
  • evidence
  • evident
  • factor
  • function
  • indicate
  • interpret
  • method
  • occur
  • require
  • significant
  • similar
  • source
  • specific
  • structure
  • theory
  • variable

The full 570-family AWL is public-domain and available from Victoria University of Wellington.

At Sonacast, Phase 4 (Independent listener, ages 7–9) content uses the top-8000 vocabulary band, which fully includes the Academic Word List. Chapter stories, curiosity episodes, and knowledge podcasts at this phase deliberately weave AWL vocabulary into narrative context — so that by the time a child meets these words in a textbook, they already know them.

A note on other languages

Dolch, Fry, and the AWL are English-specific. They exist because English has a long tradition of corpus linguistics and a large body of public-domain children's text. Equivalent frameworks exist, in various states of completeness, for other major languages — and Sonacast uses language-specific frequency bands for every locale it supports, derived from child-directed speech corpora and education-ministry literacy standards in each country.

The principle is the same in every language: begin with the highest-frequency function words and concrete nouns, expand outward through the top few thousand high-utility words, then introduce the academic vocabulary that predicts later school success. The specific words differ. The shape of the curve does not.

How this fits the bigger picture

This article answers the what. For the why — the developmental science behind each phase, the research on imagination, emotional intelligence, curiosity, and attention that sits alongside vocabulary — the companion article is How the first years of listening shape a child's entire future.

Together, the two articles describe the full research foundation we use at Sonacast to decide what every story should contain at every age: which words a child is ready for, how many new ones to introduce per story, how to repeat them, what sentence structures to use, and what developmental goals to weave in alongside vocabulary. None of this is invented. It is simply the best of a century of linguistic and developmental research, translated into audio a child can enjoy.

If you are a parent reading this: you do not need to drill these words. You just need to make sure your child hears them — often, in context, in stories they love. That is the whole mechanism.

Sources

Human in the loop
Kai Lemmetty

Co-founder of Sonacasts. Marketer turned product builder who started coding AI apps in 2024.

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