Baby sign language: An evidence-based guide

© 2018 Gwen Dewar, Ph.D., all rights reserved

What is "baby sign language"?

The term is a bit misleading, since it doesn't refer to a genuine language. A true language has syntax, a grammatical structure. It has native speakers who converse fluently with each other.

By contrast, baby sign language, also known as baby signing, refers to the act of communicating with babies using a modest number of symbolic gestures.

Parents talk to their babies in the usual way – by speaking words – but they also make use of these signs. For instance, a mother might ask, "Do you want something to drink?" while making the sign for "drink."

Where do these signs come from? That depends.

Some signs might arise spontaneously, when we try to act out an idea with hand movements.

You and your baby see a butterfly, so you flap your hands as you say the word aloud. Or you notice that your baby waves her hand dismissively when she doesn't want something, as if she is trying to push it away.

The signs begin as a kind of improvised pantomime, but you find yourself using them again, on subsequent occasions. They become part of your family's signing vocabulary.

But for many people, the phrase "baby sign language" means something else: learning a set of signs provided by charts, books, or videos.

And many of these signs lack the "acting out," pantomime element. As Lorraine Howard and Gwyneth Doherty-Sneddon (2014) note, there has been a trend for commercial baby language programs to borrow signs from languages for the deaf, like American Sign Language (ASL).

Some of these have the quality of iconicity. Their form resembles the idea they stand for.

The ASL sign for "drink," for example, looks like you're holding a cup to your mouth:

But other signs are not iconic. You can see this here, in the signs for "play," "hurt," and "mother," all adapted from ASL:



The mapping of the gestures to their meanings is arbitrary, just as it is for most spoken words.

Does it matter if a sign is iconic (pantomime-like) or arbitrary?

Research suggests that it does. As long as you possess the necessary background information (that people drink from cups), you are going to find it easy to connect the sign (the ASL gesture for "drink") with the idea (drinking). And that will help you learn and remember the sign going forward.

Studies confirm that babies tend to learn iconic signs more readily than arbitrary ones (Thompson et al 2012). 

So should you teach your baby signs? What are the benefits of baby sign language?

Teaching a baby to communicate using gestures can be exciting and fun. It's an opportunity to watch your baby think and learn.

The process might encourage you to pay closer attention to your baby's attempts to communicate. It might help you appreciate the challenges your baby faces when trying to decipher language.

These are good things, and for some parents, they are reason enough to try baby signing.

But what about other reasons -- developmental reasons?

Some advocates claim that baby signing programs have long-term cognitive benefits.

They claim that babies taught to sign will amass larger spoken vocabularies, and even develop higher IQs.

Others have claimed that signing has important emotional benefits.

According to this argument, babies learn signs more easily than they learn words. As a result, they communicate more effectively at an earlier age. Their parents understand them better, reducing frustration and stress.

Does the research support these claims?

Not really. But it depends on what you mean by baby-signing.

If by "baby signing" you mean "teaching babies signs derived from ASL or other languages," then there's no compelling evidence of long-term advantages.

But if you're thinking of the more spontaneous, pantomime use gesture, it's a different story. There is good evidence suggesting that easy-to-decipher, iconic gesturing can help babies learn.

To see what I mean, let's take a closer look at the research.


Do baby signing programs boost long-term cognitive skills?

Overall, the evidence is lacking.

The very first studies hinted that baby sign language training could be at least somewhat advantageous, but only for a brief time period (Acredolo and Goodwyn 1988; Goodwyn et al 2000).

In these studies, Linda Acredolo and Susan Goodwyn instructed parents to use baby signs with their infants. Then the researchers tracked the children across 6 time points, up to the age of 36 months.

When the children’s language skills were tested at each time point, the researchers found that babies taught signs were sometimes a bit more advanced than babies in a control group.

For instance, the signing children seemed to possess larger receptive vocabularies. They recognized more words.

But the effect was weak, and detected only for a couple of time points during the middle of the study.

For the last two time points, when babies were 30 months and 36 months old, there were no statistically significant differences between groups (Goodwyn et al 2000).

In other words, there was no evidence that babies benefited in a lasting way. 

More recent studies -- using stringent controls -- have also failed to find any long-term vocabulary advantage for babies taught to sign (Johnston et al 2005; Kirk et al 2012; Fitzpatrick et al 2014; Seal and DePaolis 2014).

For example, Elizabeth Kirk and her colleagues (2012) randomly assigned 20 mothers to supplement their speech with symbolic gestures of baby sign language. The babies were tracked from 8 months to 20 months of age, and showed no linguistic benefits compared to babies in a control group.

And IQ? 

Although some advocates have claimed that baby sign language training boosts a child's IQ, the relevant research has yet to appear in any peer-reviewed journal. On this question, it's safe to say that the jury is still out. 

What about giving babies a voice? Is it true that babies can sign before they can speak?

This is an interesting idea, and it has been championed by advocates of baby signing programs.

The proposal is that babies -- particularly babies under the age of 2 -- are capable of communicating via sign language months before they are ready to communicate with spoken language. 

Is there compelling scientific evidence for this claim? Once again, the answer is no.

Research on the development of signing -- in babies who are deaf, or born to deaf parents -- provides us with hints. 

For example, in a study tracking the development of 11 babies raised by deaf parents, babies produced their first recognizable signs at around 8.5 months (Bonvillian et al 1983).

And another study assessed the productive, signing vocabulary of 12 deaf children between the ages of 12 and 17 months. On average, these babies produced about 62 different ASL signs (Anderson and Reilly 2002). 

So these studies give us a rough idea of how signing might develop in the average child. What about the development of speech?

As I explain in this article about babies' first words, there's reason to think that some babies may be speaking their first words as early as 6 months. And according to a survey of more than 1500 parents, most babies are speaking their first words by 10 months.

As for the number of words spoken, we have information about that, too. In an influential study from 1994, researchers assessed a group of 16-month-old children -- 64 individuals in all -- and found that these babies produced an average of 40 different spoken words (Fenson et al 1994, p.37).

But the test they used is known to underestimate the true number. More recent research, published in 2011, suggests that figure is closer to 74 spoken words (Mayor and Plunkett 2011).

So we have research about both signing and speaking, but the studies are hard to compare.

At first glance, it might appear that signing babies have an advantage. In particular, the babies in the ASL study seem to have developed large productive vocabularies.

But is there really a difference here?

Language research reveals that there is a tremendous individual variation. For example, in the 1994 study of speech development, 10% of the 16-month-old babies could produce 180 words or more. Another 10% could produce only 9 words or fewer.

And the ASL results are based on a very small number of individuals -- only 12 babies between the ages of 12 and 17 months. As everyone knows, it's easy to get skewed results with a small sample. Maybe the ASL study just happened to include a few whiz kids -- a disproportionate number of babies with an aptitude for language.

Moreover, as language researcher Richard Meier notes, we can't compare studies if they don't use a common yardstick for evaluating whether or not a baby's efforts should count as a "real" sign or spoken word.

Whether it's speech or gesture, babies' early attempts to communicate are imperfect. Their words don't sound like adult words. Their gestures don't perfectly match up with the official signs. They produce approximations of the correct words and signs, and researchers must decide how to evaluate them. To date, studies have taken different approaches to this problem. 

So it's not clear that babies can learn to sign before they can learn to speak. It's possible, but unproven. We need more research to decide the question (Meier 2016).

And the social and emotional benefits? Is there evidence that baby signing reduces frustration or stress?

People might experience benefits at an individual level, but without controlled studies, it's hard to know if it's really the signing that makes the difference. It's also hard to know if the effect is general – something most families would experience if they tried it.

To date, claims about stress aren't well-supported. One study found that parents enrolled in a signing course felt less stressed afterwards, but this study didn't measure parents' stress levels before the study began, so we can't draw conclusions (Góngora and Farkas 2009).

By contrast, there are hints that signing may help some parents become more attuned to what their babies are thinking.

In the study led by Elizabeth Kirk, the researchers found that mothers who had been instructed to use baby signs behaved differently than mothers in the control group. The signing mothers tended to be more responsive to their babies' nonverbal cues, and they were more likely to encourage independent exploration (Kirk et al 2012).

So perhaps baby signing encourages parents to pay extra attention when they communicate. Because they are consciously trying to teach signs, they are more likely to scrutinize their babies' nonverbal signals. As a result, some parents might become better baby "mind-readers" than they might otherwise have been.

But of course parents don't need to participate in a baby sign language program to achieve these effects. The important thing is tuning into your baby, and figuring out what he or she wants. Which brings me to another point...

You can communicate a lot without using formal "baby signs"

For example, consider this sign for "more," borrowed from ASL. It's a perfectly useful sign, and many babies have learned it.

But what happens if you don't teach your baby this sign? Will your baby be incapable of letting you know that he wants more applesauce? Will your baby somehow fail to get across the message that she wants to play another round of peek-a-boo?

When parents pay attention to their babies -- and engage them in conversation, one-on-one -- they learn to read their babies' cues.

A baby might pat the table when he wants more applesauce. A baby might reach out and smile when she wants to play with you. They aren't signs borrowed from a language like ASL, but, in context, their meaning is clear.

When we respond appropriately to these spontaneous gestures, we are engaged in successful communication, and we are helping our babies build the social skills they need to master language.

In fact, our ability to read and use such gestures really matters.


How nonverbal cues can help babies learn language

Imagine I stranded you in the middle of a remote, isolated nation. You don't speak the local language, and the locals don't recognize any of your words. What would you do?

Very quickly, you'd resort to pantomime. And as you tried to learn the language, you'd soon appreciate that some people are a lot more helpful than others.

It isn't just that they're friendlier. Some people just seem to have a better knack for non-verbal cues. They follow your gaze, and comment on what you're looking at. They point at the things they are talking about.

They use their hands and facial expressions to act out some of the things they are trying to say. And they're really good at it. When they talk, it's easier to figure out what they mean.

Researchers call this ability "referential transparency," and it helps babies as well as adults. The evidence?

Erica Cartmill and her colleagues (2013) made video recordings of real-life conversations between 50 parents and their infants – first when the babies were 14 months old, and again when they are 18 months old.

Then, for each parent-child pair, the researchers selected brief vignettes – verbal interactions where the parent was using a concrete noun (like the word "dog," or the word "ball.")

The researchers muted the soundtrack of each vignette, and inserted a beeping noise every time the parent uttered the target word. Next, they showed the resulting video clips to more than 200 adult volunteers.

They asked the volunteers to guess what the parents were talking about. When you hear the beep, what word do you think the parent is saying?

The researchers were pretty tough graders. They didn't, for example, count guesses as correct if they were too general (like guessing "toy" when the correct answer was "teddy bear."

They also didn’t give volunteers credit for guesses that were too specific (guessing "finger" when the correct answer was "hand"). They also tried to eliminate vignettes where it was possible for volunteers to read the parents' lips.

So the test wasn't easy, and it might give us an idea of how challenging it is for babies to decipher unfamiliar words. The results?

It turns out there was a lot of variation between parents. Some parents spoke with referential transparency only 5% of the time. Others were more like expert foreign language teachers, making their meanings clear up to 38% of the time.

And — here's the part with implications for the long-term — there were links between a parent’s referential transparency score and her child’s vocabulary three years later.

Babies who had more "transparent" parents tested with larger vocabularies when they were four and half years old.

The link remained significant even after controlling for the babies’ vocabularies at the beginning of the study, and there were other interesting points too.

Although the sheer number of works spoken by parents predicted a child’s vocabulary, it was quality, not quantity, that mattered most. And while researchers replicated a well-known finding – that parents of higher socioeconomic status (SES) use more words with their kids – there were no links between SES and referential transparency.

Parents of high SES were no more likely than other parents to speak to their babies in a highly transparent way.

What do we make of these results?

We can't be sure that referential transparency caused larger vocabularies. Maybe parents who scored high on referential transparency did so because they possessed a heritable trait – one they passed on to their kids – that makes people both better communicators and better verbal learners.

But it's not hard to imagine how referential transparency could lead to long-term language gains. And other research suggests that we can help our babies by being responsive to our babies' spontaneous gestures.

For example, consider the importance of pointing.

Babies learn words faster when we label the things they point at

Most babies begin pointing between 9 and 12 months, and this can mark a major breakthrough in communication. Babies learn that they can make their wishes known by making eye contact and then shifting the direction of your gaze.

By pointing, babies can make requests (e.g., "Give me that toy.") They can also ask questions ("What is that?") and make comments ("Look at that!").

It's a major communicative breakthrough -- and watershed learning tool -- if we pay attention and respond appropriately.

As psychologists Jana Iverson and Susan Goldin-Meadow have noted, a baby who points at a new object might prompt her parent to label and describe the object. 

If the parent responds this way, the baby gets information at just the right moment—when she is curious and attentive. And that could have big implications for learning (Iverson and Goldin-Meadow 2005).

Experiments have confirmed the effect: Babies are quicker to learn the name of an object if they initiate a "lesson" by pointing.

Adults can also respond to a baby's gaze or reaching gestures. But the most potent learning effect is associated with a baby pointing. 

And if the adult tries to initiate? Labeling an object that the baby didn't point at? Then there is no special learning effect (Lucca et al 2018).

So all this makes me think that gestures matter a great deal. But the trick is to emphasize referential transparency.

We want to be like that those language tutors in the remote, far-off country – the ones who respond to other people's requests for information, and who have a knack for supplementing speech with easy-to-understand pantomime.

Does this mean that abstract, non-iconic signs pose a problem? Does baby sign language training delay speech development?

Studies haven't found that babies trained to use signs suffer any disadvantages. So if you and your baby enjoy learning and using signs, you shouldn't worry that you're putting your baby at risk for a speech delay. In essence, you're just teaching your baby extra vocabulary -- vocabulary borrowed from a second language. 

Still, it's useful to remember that iconic gestures are easier for your baby to figure out.

For example, in one experimental study, 15-month-old toddlers were relatively quick to learn the name of a new object when the adults gestured in an illustrative, pantomime-like way.

The toddlers were less likely to learn the name for an object when the spoken word was paired with an arbitrary (non-representational) gesture (Puccini and Liszkowski 2012). 

So what's the takeaway?

Non-verbal communication is crucial for language development. Gestures can provide babies with important information, and help them decipher your meaning. 

But not all gestures are equally helpful. Research suggests that the most effective approach is

  1. to pay attention to our babies, and respond appropriately to their spontaneous attempts to gesture and verbalize; and
  2. to communicate with babies using a combination of speech and transparent gestures -- like pantomime and pointing.

In addition, I suspect it's beneficial to build on those signs and gestures that you and your baby spontaneously invent. They already have meaning to your baby, and they are probably easier for your baby to remember.

This doesn't mean you shouldn't also teach your baby sign language, including some arbitrary, non-iconic signs. It can be fun and interesting, and your child might end up learning signs that are very useful.

But to help your baby learn, it makes sense to emphasize gestures that are easy to decipher, and which have personal meaning to your baby.


Tips for teaching baby sign language

Whether you opt for the spontaneous, do-it-yourself approach, or you want to teach your baby gestures derived from real sign languages, keep the following tips in mind.

1. You can start early.

Babies begin learning about language from the very beginning. They overhear their mothers’ voices in the womb, and they are capable of recognizing their mother’s native language – distinguishing it from a foreign language – at birth.

Over the following months, their brains sort through all the language they encounter, and they start to crack the code. And by the time they are 6 months old, babies show an understanding of many everyday words – like “mama," “bottle," and “nose."

Many babies this age are also babbling – repeating speech syllables like “ma ma ma" and “ba ba ba."

If a 6-month-old baby says “ba ba" after you give her a bottle, could it be that she’s trying to say the word “bottle"? If an infant sees his mother and says “mama," is he calling her by name?

It’s entirely possible. And in any case, modern surveys suggest that most babies are speaking their first words by the age of 10 months. (Read more about it in my article, “When do babies speak their first words?")

So given what we know about language development in babies, we might expect that babies are ready to observe and learn about signs at an early age -- even before they are 6 months old.

2. Introduce signs naturally, as a part of everyday conversation, and don't try to "drill" babies.

Babies learn words and signs by being repeatedly exposed to them, and by using them in real conversations. So let your signs come up naturally, and avoid turning these episodes into parent-driven lessons. Remember the experiments about pointing. Babies learn when they're the ones who initiate.

3. Keep in mind that it's normal for babies to be less than competent. Don't pretend you can't understand your baby just because his or her signs don't match the model.

Just a baby's first attempt to say "bottle" falls short ("ba ba,") his or her early attempts to gesture will likely be less than perfect.

Baby sign language instructors call these attempts "sign approximations," and they recommend that you run with them. In some cases, your baby might lack the manual dexterity to form the correct version of the sign.

Pretending that your baby didn't really communicate effectively to you -- because your baby's gesture isn't exactly what you want -- is counter-productive. 

Don't forget: Babies develop better language skills when their parents are tuned in and helpful!

More reading

For more information about communicating with babies, see this review of fascinating research about the effects of eye contact on infants. It discusses how shared gaze primes your baby's brain for communication and language-learning.

In addition, see this article about how certain aspects of infant-directed speech help babies learn language.


References: Baby sign language

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Acredolo L and Goodwyn S. 1998. Baby Signs. Chicago: Contemporary Books.

Anderson D and Reilly J. 2002. The MacArthur Communicative Development Inventory: Normative data for American Sign Language. Journal of Deaf Studies and Deaf Education 7: 83–106

Bonvillian JD, Orlansky MD, Novack LL. 1983. Developmental milestones: sign language acquisition and motor development. Child Dev. 54(6):1435-45.

Cartmill EA, Armstrong BF 3rd, Gleitman LR, Goldin-Meadow S, Medina TN, Trueswell JC. 2013. Quality of early parent input predicts child vocabulary 3 years later. Proc Natl Acad Sci USA  110(28):11278-83.

Crais E, Douglas DD, and Campbell CC. 2004. The intersection of the development of gestures and intentionality. J Speech Lang Hear Res. 47(3):678-94.

Fenson L, Dale PS, Reznick JS, Bates E, Thal DJ, Pethick SJ. 1994. Variability in early communicative development. Monogr Soc Res Child Dev. 59(5):1-173.

Fitzpatrick EM, Thibert J, Grandpierre V, and Johnston JC. 2014. How handy are baby signs? A systematic review of the impact of gestural communication on typically developing, hearing infants under the age of 36 months. First Language. 34 (6): 486–509.

Goodwyn SW, Acredolo LP, and Brown C. 2000. Impact of symbolic gesturing on early language development. Journal of Nonverbal Behavior. 24: 81-103.

Howard L and Doherty-Sneddon G. 2014. How HANDy are baby signs? A commentary on a systematic review of the impact of gestural communication on typically developing, hearing infants under the age of 36 months. First Language 34(6):510-515

Iverson JM and Goldin-Meadow S. 2005. Gesture paves the way for language development. Psychological Science 16(5): 367-371.

Iverson, J.M., Capirci, O., Volterra, V., & Goldin-Meadow, S. (in press). Learning to talk in a gesture-rich world: Early communication of Italian vs. American children. First Language.

Johnston JC, Durieux-Smith A and Bloom K. 2005. Teaching gestural signs to infants to advance child development: A review of the evidence. First Language 25(2): 235-251.

Kirk E, Howlett N, Pine KJ, Fletcher BC. 2013. To Sign or Not to Sign? The Impact of Encouraging Infants to Gesture on Infant Language and Maternal Mind-Mindedness. Child Dev. 84(2):574-90.

Lucca K and Wilbourn MP. 2018. Communicating to Learn: Infants' Pointing Gestures Result in Optimal Learning. Child Dev.  89(3):941-960.

Mayor J and Plunkett K. 2011. A statistical estimate of infant and toddler vocabulary size from CDI analysis. Developmental Science 14(4): 769-85.

Meins E, Fernyhough C, Fradley E, and Tuckey M. 2001. Rethinking maternal sensitivity: Mothers’ comments on infants’ mental processes predict security of attachment at 12 months. Journal of Child Psychology and Psychiatry and Allied Discipline 42: 637-648.

Meyer RP. 2016. Sign language acquisition. Oxford Handbooks Online. DOI: 10.1093/oxfordhb/9780199935345.013.19

Oller DK. 2000. The emergence of the speech capacity. Lawrence Erlbaum.

Petitto LA. 1988. “Language" in the prelinguistic child. In F. S. Kessel (ed.), The development of language and language researchers: Essays in honor of Roger Brown (pp. 187–221). Hillsdale, NJ: Lawrence Erlbaum.

Petitto LA and Marentette PF. 1991. Babbling in the manual mode: Evidence for the ontogeny of language. Science 251: 1493-1496.

Puccini D and Liszkowski U. 2012. 15-Month-Old Infants Fast Map Words but Not Representational Gestures of Multimodal Labels. Front Psychol. 2012;3:101. Epub 2012 Apr 3.

Seal BC and DePaolis RA. 2014. Manual Activity and Onset of First Words in Babies Exposed and Not Exposed to Baby Signing. Sign Language Studies 14(4): 444-465.

Thompson R, Vinson DP, Woll B, and Vigliocco G. 2012. The road to language learning is iconic: Evidence from British Sign Language. Psychological Science 23: 1443–1448

title image of gesturing baby boy and father by David R Tribble / wikimedia commons

image of pointing infant on the lap of his father by Quinn Dombrowski / flickr

image of baby signs by Dr. Michael Fetters, University of Michigan

Portions of this text appeared in an earlier version of the article by the same name. In addition, some of the sentences about Cartmill's study original appeared in a blog post for BabyCenter.

Content last modified 12/2018



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