How many words should an 18-month-old say?

The number

The CDC’s 2022 checklist puts one item under “language” at 18 months: tries to say three or more words besides “mama” or “dada”.¹ That is deliberately a floor, not an average — the 2022 revision moved every milestone to the age by which three-quarters of children do it, so that a child who has not is worth a look rather than a shrug.

The average is much higher. On the MacArthur-Bates inventory — the 680-word checklist parents fill in, which is where nearly every vocabulary statistic comes from — the typical 18-month-old is credited with somewhere around 50 words, and the normal range at that age runs from a handful to well over a hundred.^{2, 3} The original norming study called the variability “enormous” and meant it: a child at the tenth percentile and a child at the ninetieth are both developing normally, and they can differ by a hundred words.²

What counts as a word

More than you might be counting. The research inventories count a word if the child uses a consistent sound for a consistent meaning, whether or not it is pronounced correctly.² That means:

• Approximations count. “Ba” for ball, “gog” for dog, “nana” for banana — if it means the same thing every time, it is a word.
• Sound effects count. “Woof”, “vroom”, “uh-oh” and “yum” are on the inventory and are among the earliest words in every language studied.⁴
• Signs count. A consistent gesture for more or all done is a word.
• Names count, including the dog’s and the grandparents’.
• Both languages count. A bilingual toddler’s leche and milk are two words on the list (and one concept). Never count one language alone.⁵

Parents who keep a running list on their phone for a week are usually surprised by the total. It is also the single most useful thing to bring to a pediatrician.

What to watch instead of the count

Understanding. At 18 months a toddler understands far more than they say — typically several times as many words.² Can they follow “go get your shoes” without a gesture? Point to the right picture when you name it? Look at the dog when you say “dog”? A child who understands a lot and says little is a child whose words are on their way; receptive language is the best single predictor of where a late talker ends up.⁶

Gestures and joint attention. Pointing at things to show you, bringing you objects, looking where you point, waving. These are the machinery of language and they come before the words.

Trajectory. New words appearing, even slowly, is the reassuring pattern. Words disappearing is not, at any age — that is a same-week call.

The two flags worth a call

Out of everything on the milestone lists, two things at this age reliably warrant a hearing check and a speech-language evaluation:^{1, 7}

• No words at all by 18 months (not even approximations or signs), or
• Not pointing, waving, or responding to their name — the gesture and attention side, regardless of words.

Neither means something is wrong. Both mean a check is the sensible next step, and in the U.S. the check is free through every state’s early-intervention program. The late-talker guide walks through what it involves and what the follow-up studies show.

About the “word spurt”

You will read that vocabulary “explodes” around 18 months. For some children it does; for many the growth is steady rather than sudden, and a careful re-analysis found that a true spurt is the exception rather than the rule.⁸ If your child is adding a few words a week rather than a dozen a day, nothing is wrong with the curve.

What helps

The things that grow an 18-month-old’s vocabulary are ordinary and they are all done by a person: naming what the child is looking at, in the moment;⁹ talking during routines, because routines repeat; leaving a pause after you speak so the attempt can happen; and treating every approximation as the word it is. A picture with the word said warmly on top is a tool for that — the free cards are the everyday words that fit routines, and they print if you would rather keep the phone in your pocket.