Number of Words in a Child’s Vocabulary

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SLPs and therapists who work in early intervention and preschool programs are often surprised when we take a minute to look at normal expressive language development. Most of the time, it’s because our perceptions of “normal” become skewed over time. We administer tests and come to think of those test questions and the age ranges listed on the assessment tool as “average” when in fact, they’re not.

Let me remind you of the average number of words a child with typically developing language has during this developmental period.

Approximate Words in Expressive Vocabulary in Typically Developing Toddlers

By 12 months a child says 2-6 words other than  Mama or Dada?

By 15 months a child says 10 different words.

At 18 months toddlers with typically developing language use 50 different words.

At 24 months a child with typically developing language says 200-300 words.

By 30 months a toddler says 450 words.

At 36 months a child with typically developing language uses 1,000 different words.

**LinguiSystems Guide to Communication Milestones cites sources as Child Development Institute at Nicolosi, Harryman, Kresheck (2006). Owens (1996).

Contrast this information with milestones used in common speech-language assessments for infants and toddlers.

Most assessment tools include the skill, “Child says 50 words by 24 months.”

What’s the discrepancy here?

Even those of us who aren’t great with math can see that a child who is using 50 words by 24 months lags behind his or her typically developing peers who are using 200 to 300 words.

Remember that the milestones on speech-language tests are based on when 90% of all children have mastered the skill.

This means the majority of toddlers, usually 90%, are using 50 different words by 24 months.
It does not mean that a toddler with “average” skills says 50 words by 24 months.

Milestones are NOT an “average” number of words achieved by a particular age or when children functioning in the “average” range at the 50th percentile have achieved the skill.

A researcher would tell you that the variance is there to account for the full range of normal development. I do recognize and appreciate that fact about development. Every baby boy or girl will develop in his own time and at her own pace.

However, what about the parent or even the professional who doesn’t realize that there are differences in the milestones we use and true typical development? What if they don’t understand that late talking is already built in to this data? What about the mom who surmises, “Well, a normal girl may say 50 words by 24 months, but I have a boy, and boys talk later than girls.” What about the pediatrician who falsely believes that the language milestones are listed as “averages” and that a kid with only 25 words by the time he’s 2 is bound to be okay based on wanting a child to say 50 words at 2?

I cringe whenever I read an article that recommends a child get a speech-language evaluation if he’s not using 25 words by age 3 since all children develop differently.

A child who is only using 25 different words at 3 exhibits a SIGNIFCANT language delay when compared with his same age peers who are using 1,000 different words.

Within our own field there can also be a level of misinformation provided by well-intentioned therapists. Here’s a scary, but true story to illustrate this point.

Several years ago a highly-educated mother told me that she asked the speech-language pathologist who was seeing her daughter, who then was 21 months old with fewer than five consistent words, how her daughter’s vocabulary would ever catch up to meet the 50 word milestone by her second birthday.

Do you know what the SLP’s response was?

This is a direct quote the mother shared with me, “Oh, none of my kids ever have 50 words by 2. That’s ridiculous!”

The mom told me that she was shocked by this response. She then said to the speech pathologist, “That’s because all the kids you’re seeing are delayed and are getting speech therapy, right?”

I could hardly wait for the mom to tell me the therapist’s reply. Surely she realized that she had misspoken. When I asked this mother what she said then, the reply was just as shocking. The SLP said she had never thought about it in that way before.

Did you cringe when you read this story? I still do every time I think about it, and not only for the mother who began to question the competence of the person seeing her child. I’m sure we can all also sympathize with the professional who was obviously caught off-guard and likely very self-conscious about her misstep once she realized what she’d said. Many of us are quite good at remembering stupid things we’ve said and then quickly wished we could take back. Are you flashing back to your own highlight reel of embarrassing moments?

However, there’s a lesson in this story for all of us. At the heart of this situation is a speech-language pathologist who doesn’t understand the milestones. She falsely believes that 50 words by 2 is the recommendation for the average of the developmental charts! Hopefully this story will help us all remember to do better.

While this information about vocabulary size doesn’t change who will and won’t be eligible for services, it certainly does impact how I share information with families. I painstakingly explain the milestones to parents stating that the number of words the doctor mentioned or that the statistic Mom read in a magazine is really a minimal expectation.

When a little boy scores in the 15th percentile on a test I administer, I explain that 85% of all children tested in his age range during the standardization process scored better than her child did. If a child’s standard score on a test is 100, I go out of my way to explain that a standard score is scaled differently and the 100 on this test means that he’s at the 50th percentile, right smack in the middle average, not that he answered 100% of the questions correctly during the assessment. (By the way, neither of those children need speech! Children who qualify for services are often in the bottom 1 to 5th percentiles.)

Professionals owe it to parents to provide accurate information about their child’s performance as well as what we know about typical development.

In order to do that, we need to make sure our own information about typical development is grounded in research about typical development and nothing else.

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  1. ShawnaLee on May 10, 2015 at 4:45 pm

    Great post. I know my view of normal was skewed after working with delayed children for years. Having my own kids brought my measuring stick back to center. When I saw “average” kids I used to be amazed at what they could do. Great reminder.

    • Laura on May 10, 2015 at 6:07 pm


  2. Sarah Fukuda on May 13, 2015 at 4:53 pm

    Thank you for sharing this information!!

  3. Sylvia Kinney on May 29, 2015 at 1:44 am

    My grandson has a hard time pronouncing his words.. I know it’s a struggle to communicate with his class mates, I know he gets frustrated and shy away from talking. This upsets me. I would like to know if your program helps young children at his age ? He just turned 6 years old in February of this year . I so much appreciate you contact me soon as possible I need a direction of where I can receive help if your unable to assist me..
    Thank you very much
    Sylvia Kinney
    Cell # 775-378-9293

    • Laura on May 30, 2015 at 3:17 pm

      Hi Sylvia. I specialize in babies and toddlers, so 6 is OLD for me : ) Is he getting speech therapy? That’s where I would begin by helping his mom find a place to have him evaluated and treated. If you’re in the US, therapy is available in all public schools or at private clinics, university speech and hearing clinics and children’s hospitals. Of course you can work with him at home, but if he’s having so much difficulty that he’s frustrated and avoids talking, then he really does need professional intervention. The SLP will be able to help you know how to work with him at home too. Good luck to you all!! Laura

  4. Art on September 27, 2016 at 2:15 am

    Hello Laura I currently have a toddler who’s speech is delayed yet I do not have the money at this time to pay the deductible in order to get him the help he needs to hire a professional. I believe his delay may be my fault. Due to not interacting enough with him. I am going to set aside more hours in the day for him. My question is what words should I start with. He can say daddy, mom, babe, bye, where you going. He is currently 2 years old. We do spend time with him however I feel we lack the proper training to teach him how to talk. I watched some of your youtube videos and I’m going to purchase some puzzles. I think in one video you talk about starting with some fundamental words is there a video were you mention them and how can I introduce them to him.

  5. Emil on November 15, 2016 at 11:03 am

    Hi Laura, this was an eye opener for me! Not about what average kids can do, but about how milestones can be misguiding. I have a 20 month old son who understands a lot of words but is not really saying much that makes sense yet (I know why that is, and we are about to see an SLP). For several months now I have been tracking his progress per the usual milestones, and he was not that far behind – but compared to his playmates the difference is obvious. Now I understand why!

    I stumbled upon your great article while doing research for my own blog post listing vocabulary milestones (yes, I need to learn all that for my son, so I thought why not share it in a blog ). I did end up using the normal milestones, as I don’t feel confident enough to say otherwise – but I put in a small notice about understanding what is really average with a link to your article. If you are interested please have a look at what I wrote here:

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