How Many Words Should a 20-Month-Old Say?

Most 20-month-olds say somewhere between 50 and 200 words, but the range of what counts as typical is surprisingly wide. Some toddlers at this age are stringing two-word phrases together while others are still hovering around a couple dozen words and communicating mostly through pointing and gestures. The research on early vocabulary makes one thing clear: there is no single number a 20-month-old “should” hit, and the factors shaping that number are more varied and interesting than most parents realize.

What Typical Actually Looks Like at 20 Months

Developmental researchers track early vocabulary primarily through parent-report tools like the MacArthur-Bates Communicative Development Inventories (CDI), where caregivers check off words their child says from a standardized list. These tools have been refined over decades and consistently show that vocabulary at 20 months follows a dramatically skewed distribution. The median sits around 50 to 75 spoken words, but the 10th percentile can be as low as about 10 words while the 90th percentile can top 200. That is not a sign that something is wrong with most kids at either end. It reflects a genuine and well-documented spread in the pace of early language learning.

Part of what makes the range so dramatic is the vocabulary spurt, a phase where word learning accelerates noticeably after a child has built up a critical mass of about 50 words. Research tracking individual children’s vocabulary growth curves finds that roughly three-quarters of infants show a clear spurt in at least one vocabulary type, though the timing varies. For some children the spurt kicks in before 18 months; for others it does not arrive until well past the second birthday. Infants who hear more language in a given language tend to reach the spurt earlier in that language.

1PubMed Central. Testing theories of the vocabulary spurt with monolingual and bilingual infants

So if your 20-month-old is at 30 words and your friend’s child the same age is at 150, both can be perfectly on track. The child with fewer words may simply be on the verge of a spurt that has not arrived yet. What matters more than hitting a specific number is the trajectory: is the word count growing week to week, even slowly?

What Kinds of Words Come First

Not all early words are created equal. Across most languages studied, children’s first vocabularies lean heavily toward nouns, and specifically toward names for objects they can see and touch. An analysis of vocabulary composition in children around 20 months found that nouns outnumbered all other word classes, though only about half of those nouns were names for everyday object categories like “ball,” “dog,” or “cup.” The rest included proper names, body parts, and food items.

2Journal of Child Language. Nouns in early lexicons: evidence, explanations and implications

This noun-heavy pattern holds across many different languages, though the degree of the bias varies. A systematic review of cross-cultural research found general support for a noun advantage, but the size of that advantage depended partly on the language itself. Languages with rich verb morphology, for instance, sometimes show children picking up verbs earlier. In one study of Xitsonga-speaking children, the noun bias was present in smaller vocabularies but children shifted toward favoring verbs once their vocabulary exceeded about 400 words.

3PubMed Central. Cross-Cultural Variation in the Noun Bias in Early Vocabulary Development: A Systematic Review4First Language. Examining Noun Bias in the Vocabulary Development of Xitsonga-Speaking Children Aged 16 to 32 Months

For parents counting words at home, this means that a 20-month-old’s vocabulary is likely dominated by names of people, animals, foods, and toys. Social words like “hi,” “bye,” and “no” tend to show up early too. Action words like “go,” “eat,” and “give” are starting to appear but are usually a smaller slice of the total. If your toddler’s word list is almost entirely nouns, that is perfectly expected.

Why Some 20-Month-Olds Talk More Than Others

Parents often wonder whether a child’s vocabulary is somehow their “fault” or if it is baked in genetically. The honest answer is that it is both, but the balance is not what you might expect. A twin study looking at individual differences in toddler expressive language found that shared environment, meaning things like the household language environment, parenting style, and socioeconomic context, accounted for the majority of variation in both boys and girls, explaining between 54% and 78% of individual differences in vocabulary. Heritability played a smaller role, contributing roughly 8% to 20% of the variation depending on the outcome and the child’s sex.

5PubMed. Genetic, environmental, and gender effects on individual differences in toddler expressive language

That finding lines up with what researchers see in the field: the language environment a child grows up in matters a great deal. But several specific factors beyond “how much you talk to your kid” are worth knowing about.

Gender

Girls tend to produce more words than boys at this age. One large study found a moderate-to-large difference, with girls using more unique words than boys and the gap widening as children got older.

6PubMed Central. Talking to talkers: Infants’ talk status, but not their gender, is related to language input

Research with French Canadian children between 8 and 30 months confirmed this pattern, finding that girls not only produced more words but also used more grammatical forms and more complex sentences. The researchers noted that this gender difference is real enough that clinicians should keep it in mind when evaluating whether a toddler’s vocabulary is on track.

7Applied Psycholinguistics. Gender differences in language development in French Canadian children between 8 and 30 months of age

Interestingly, the same study that found girls producing more words found no meaningful difference in how much language parents directed at boys versus girls. So the gap does not appear to be driven by parents simply talking more to their daughters.

6PubMed Central. Talking to talkers: Infants’ talk status, but not their gender, is related to language input

Birth Order and Siblings

First-born children tend to have somewhat larger vocabularies than later-born children, and the reason seems to come down to how much one-on-one adult speech a child receives. Research on children in their first 18 months found that toddlers with two or more older siblings had smaller productive vocabularies at 18 months and heard less caregiver-directed speech across several measures than peers with fewer siblings.

8PubMed Central. Analyzing the effect of sibling number on input and output in the first 18 months

But the picture is not as simple as “more siblings equals worse.” A recent study found that while birth order was negatively associated with vocabulary overall, the relationship followed a U-shaped pattern. In households where older siblings were old enough to serve as secondary caregivers, particularly older sisters, they actually contributed positively to the younger child’s language environment. The researchers developed a “child-to-caregiver ratio” measure that predicted vocabulary better than birth order alone.

9PubMed. Early Vocabulary Acquisition: From Birth Order Effect to Child-to-Caregiver Ratio

Bilingual Toddlers Need a Different Yardstick

If your 20-month-old is growing up hearing two languages, comparing their English word count to monolingual norms will almost certainly make them look behind. This is one of the most common sources of unnecessary worry among bilingual families, and the research is clear that the comparison is misleading.

When measured in a single language, bilingual toddlers consistently have smaller vocabularies than their monolingual peers. A study of UK bilingual and monolingual toddlers confirmed this: bilinguals knew fewer English words than monolinguals. But when words across both languages were added together, bilinguals actually knew more words total, for both comprehension and production. And when researchers measured “conceptual vocabulary,” counting a concept only once even if the child knew the word in both languages, the comprehension gap disappeared entirely.

10PubMed. Double it up: Vocabulary size comparisons between UK bilingual and monolingual toddlers

A separate study comparing monolingual and bilingual infants and toddlers found similar results: bilinguals had larger total word vocabularies across both languages combined but smaller single-language vocabularies and slightly smaller expressive concept vocabularies than monolinguals.

11PubMed Central. Sometimes larger, sometimes smaller: Measuring vocabulary in monolingual and bilingual infants and toddlers

The takeaway for bilingual families is straightforward: count words in both languages. A bilingual 20-month-old with 25 words in one language and 30 in the other is not “behind” a monolingual child with 50 words. They are learning the same amount of language, just distributed differently.

Gestures Are Part of the Vocabulary Picture

Parents counting spoken words sometimes overlook the communication that is happening through pointing, waving, showing, and other gestures. Researchers consider early gesture use a genuine part of language development, and in some ways it is a better predictor of future language ability than the word count itself.

A study tracking children from 14 months to 42 months found that a child’s gesture use at 14 months was a significant predictor of vocabulary size at 42 months, even after accounting for how many words the child and parent were already using at the earlier age.

12PubMed Central. Learning words by hand: Gesture’s role in predicting vocabulary development

Related research found that early gesture differences across socioeconomic groups helped explain the vocabulary gaps that children brought with them to school entry at age four and a half. Children from higher-income families used more gestures at 14 months, and this early gesture advantage accounted for much of their later vocabulary lead.

13PubMed Central. Differences in early gesture explain SES disparities in child vocabulary size at school entry

For bilingual children, the relationship between gestures and later language is even more nuanced. A study of Spanish-English bilingual children found that gesture production at 18 months predicted language outcomes at 36 months, but only in English. The researchers suggested that gesture may facilitate language-specific learning rather than acting as a general communication booster.

14PubMed Central. Gesture Production Selectively Predicts Language Outcomes in Spanish-English Bilingual Children

So if your 20-month-old is a prolific pointer and gesturer but a modest talker, that is actually a reassuring sign. The communicative intent is there, and the words tend to follow.

How Parent Talk and Screen Time Shape Early Words

The quality and quantity of speech directed at a child both matter for vocabulary growth, but they matter in different ways and at different stages. A longitudinal study found that infants who experienced more child-directed speech became more efficient at processing familiar words in real time and had larger expressive vocabularies by 24 months. Critically, speech merely overheard by the child, like adults talking to each other or television in the background, was unrelated to vocabulary outcomes.

15PubMed Central. Talking to children matters: early language experience strengthens processing and builds vocabulary

Beyond sheer volume, the variety and sophistication of the words parents use also makes a difference. Research following 50 parent-child pairs found that, even after controlling for socioeconomic status and input quantity, parents who used a more diverse and sophisticated vocabulary with their toddlers saw additional gains in their children’s later vocabulary.

16Child Development. A Longitudinal Investigation of the Role of Quantity and Quality of Child-Directed Speech in Vocabulary Development

Research on Italian families adds another layer: mothers and fathers differ in how they talk to toddlers. Mothers in the study produced longer utterances, used more word types, and tended to use nouns that were more frequent in children’s own vocabularies. Both maternal and paternal language characteristics were related to child language development, but the patterns differed.

17Journal of Child Language. Parents’ child-directed communication and child language development: a longitudinal study with Italian toddlers

Screen time, on the other hand, consistently shows a negative relationship with early language. A systematic review found that extended exposure to electronic media was negatively associated with expressive vocabulary and language skills in children.

18PubMed Central. Relationship Between Speech Delay and Smart Media in Children: A Systematic Review

A study focused specifically on 18-month-olds found that each additional 30-minute increase in daily mobile device use was associated with roughly doubled odds of parent-reported expressive speech delay.

19PubMed Central. Mobile Media Device Use is Associated with Expressive Language Delay in 18-Month-Old Children

These studies show associations, not proven causation. It could be that screen time displaces the interactive conversation that builds vocabulary, or it could partly reflect parents handing screens to children who are already less engaged with language. Either way, the pattern is consistent enough that cutting back on passive screen time and replacing it with face-to-face talk is a reasonable move.

Less Obvious Factors That Affect Word Counts

Motor Development

This one surprises a lot of parents: how well a baby sat up months ago is linked to how many words they understand later. Research tracking motor milestones and language found that the rate at which infants improved at sitting was a significant predictor of receptive language scores at both 10 and 14 months, even after controlling for other developmental factors. Grasping skill, by contrast, showed no such relationship.

20PubMed Central. Sit to Talk: Relation between Motor Skills and Language Development in Infancy

The likely explanation is that sitting frees up a baby’s hands and changes their visual perspective, allowing more joint attention with caregivers and more opportunities for the kind of interactive exchanges that build vocabulary. A child who sits stably can look where a parent points and then look back, creating the shared attention loop that underlies word learning. So if your toddler was a late sitter, their vocabulary timeline may have shifted slightly later too, and that is not necessarily a language problem in itself.

Sleep Patterns

Sleep consolidation in the first two years of life, meaning the ability to sleep in longer uninterrupted stretches, appears to be linked to language development. A longitudinal twin study found that children whose sleep was less consolidated at 6 and 18 months scored lower on subsequent language measures. By age five, children with language delays had shown less mature sleep patterns at both of those earlier time points compared to children without delays.

21PubMed Central. Associations between sleep-wake consolidation and language development in early childhood: a longitudinal twin study

This does not mean that a few rough nights of teething-related waking are going to delay your toddler’s language. The research points to chronic, ongoing sleep fragmentation as a risk factor. And since both good sleep and good language share some underlying genetic and environmental influences, the relationship is partly that the same things promoting one also promote the other.

When to Talk to a Professional

Given how wide the normal range is, how do you know when a small vocabulary actually warrants concern? Clinicians and researchers generally watch for a cluster of signs rather than a single word-count cutoff, but there are useful benchmarks. One widely used screening criterion places the concern threshold at fewer than 50 words or no word combinations by age two. The Language Development Survey, a parent-report tool validated against standardized clinical assessments, found that this cutoff had excellent sensitivity and specificity for identifying genuine language delay.

22PubMed. The Language Development Survey: a screening tool for delayed language in toddlers

At 20 months, your child still has four months before that two-year milestone, so a word count under 50 at this point is not automatically a red flag. But certain patterns do warrant earlier evaluation:

  • Limited comprehension: If your child does not seem to understand simple instructions (“give me the ball,” “where’s your shoe?”), that is more concerning than a small spoken vocabulary alone. Research on children with language delays highlights that comprehension difficulties often signal different underlying profiles than production difficulties alone.
  • Few or no gestures: A child who is not pointing, waving, or showing objects by 20 months is missing communication milestones that typically precede spoken words.
  • No response to name or social cues: Research differentiating toddlers with autism from those with developmental language delay found that children with autism showed weaker use of gaze to regulate interactions, less shared emotion, and less back-and-forth engagement, even when their spoken vocabulary was matched with language-delayed peers. Children with language delay alone, by contrast, used gestures, engaged in pretend play, and responded to language at levels that distinguished them from children with autism.
    • 23PubMed Central. Differentiating ASD from DLD in Toddlers
  • Plateau or regression: A child who was gaining words and then stopped, or who lost words they previously used, should be evaluated promptly.

Several screening tools exist for assessing language and speech delay in children under five, though they vary in accuracy. Your pediatrician can administer a quick screen at a well-child visit, and if there are concerns, a referral to a speech-language pathologist gives you the most detailed picture.

24PubMed Central. Screening for language and speech delay in children under five years

The Receptive-Expressive Gap

One thing that often reassures parents is realizing how much bigger their child’s receptive vocabulary, the words they understand, is compared to their expressive vocabulary at this age. A 20-month-old who says 30 words may understand 200 or more. That gap is completely normal and expected. Comprehension consistently runs ahead of production throughout early childhood.

Where the gap becomes clinically interesting is when it is reversed or unusually lopsided. Research on children with autism features has documented atypical receptive-expressive language profiles, where some children show a relative receptive advantage (understanding more than they say, which is the typical pattern) while others show a relative expressive advantage (saying more than they seem to understand). Children with balanced levels in both areas show a typical phenotype.

25PubMed Central. Receptive-Expressive Language Phenotypes in Infants and Toddlers With Autism Features

A separate study found that the factors predicting comprehension and production were not identical. Parental education and parental stress were related to comprehension but not to production, suggesting that spoken vocabulary development follows a stronger biological trajectory less influenced by the environment.

26Infants & Young Children. Factors Associated With Expressive and Receptive Language in French-Speaking Toddlers Clinically Diagnosed With Language Delay

For parents, the practical implication is to pay attention to understanding as well as speaking. If your 20-month-old can follow simple directions, identify objects when you name them, and respond to questions with gestures even when they are not saying much yet, their language system is working. The spoken words are likely coming; the wiring is being built underneath.