Baby sign language: An evidence-based guide

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

Toddler gesturing to father

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."

Does baby sign language work?

The short answer is yes, it works — in the sense that babies can learn to interpret and use signs. As I note below, research suggests that many babies can start producing signs by the time they are 8-10 months of age.

But the same can be said for spoken words, and, as we'll see, it's not clear that teaching babies to sign gives them any special, long-term advantages.

What signs do people use?

That depends. In some cases, families might co-opt the gestures that arise spontaneously during everyday communication.

For example, 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.

Such gestures represent a kind of pantomime. You're acting out what you're trying to say.

But
people often use the term "baby sign language" to refer to something different: teaching babies a set of signs provided by charts, books,
or videos. And many of these signs lack the 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:



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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 of gesture, that'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.

And 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 enabling better communication during infancy? Is it true that babies can sign before they can speak?



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

The proposal is that babies 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. It's not clear that the ability to use signs emerges any earlier than the ability to speak words.

To see what I mean, consider the best available research on the development of sign language acquisition — studies of infants who are either born deaf, or born to deaf parents, and taught to sign.

These studies are quite small, which makes interpretation difficult. If a few sampled babies learn to sign at a certain age, how much does this tell us about the general population? Small samples can be skewed — over-representative of individuals who are unusual.

So we can't draw firm conclusions based on these studies, but they give us a rough idea of what might be typical. What do they say?

In one study that tracked the development of 11 babies raised by deaf parents, babies produced their first recognizable signs at around 8.5 months (Bonvillian et al 1983).

Compare that with a survey of spoken language acquisition among babies who weren't deaf or raised by deaf parents. It was a large survey — more than 1500 parents answered. The results? Most parents said their babies had spoken their first words by the age of 10 months.

On the face of it, it appears that signing has the advantage. But the signing study is too small. Maybe researchers just happened to select a group of babies that learned faster than average.

We have the same problem when it comes to estimating the number of words (signed or spoken) that babies learn over time.

For example, Diane Anderson and Judy Reilly recruited families where both parents and infants were deaf, and the babies were exposed to signing from birth. The researchers measured the number of signed words that babies actually used, and found this:

Among a group of 12 babies between the ages of 12 and 17 months, the average (median) number of signs produced was 62, with individuals ranging between 7 and 107 signs (Anderson and Reilly 2002, p.89).

By contrast, in a study of speech development, researchers assessed a group of 16-month-old children — 64 individuals in all — and found that the average (median) number of words spoken was about 40. Individual babies ranged between fewer than 10 words and more than 175 (Fenson et al 1994, pp. 37-39).

So once again, a glance at the numbers makes it appear that signing has the advantage. But given the small sample sizes, and the large range of individual variation, we can't be sure.

Moreover, we'd have trouble comparing these studies even if we had larger sample sizes. One study lumps together babies between the ages of 12 and 17 months, while the other reports on 16-month-olds.

And as language researcher Richard Meier (2016) notes, we need to agree on a common yardstick for evaluating what counts as a first spoken word or sign. If a baby says "ba ba" when she means "bottle," does that count? If a baby signs "mother" by vaguely waving his hand near his chin, does that count?

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, as Meier concludes, it's too soon to say whether or not babies can learn to sign before they can learn to speak. 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?

Individual families might experience benefits. But without controlled studies, it's hard to know
if it's really learning to sign 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).

Nevertheless, 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.

And this begs the question: Does teaching your baby signs (from ASL or other languages) necessarily give you more insight into what your baby wants?

Families can communicate quite successfully without using formal "baby signs"

For example, consider this snapshot of a baby making the 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.

That doesn't mean there is no reason to teach formal signs. You might find that some signs are helpful — that they allow for communication that is otherwise difficult for your baby.

But it's wrong to think of formal signs as the only gestures that matter. From the very beginnings of humanity, parents and babies have communicated by gesture. And research suggests that gestures matter. A lot!

Why everyday gestures can have a big impact on your baby's development

1. Our 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 "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").

Nor did they 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
outcome?

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 high-quality, transparent communication 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 remember: Parents with high referential transparency were easier for adult volunteers to understand, and these adults were unrelated to the parents.

So it isn't 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.

2. 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.

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!").

But the impact of this communicative breakthrough depends on our own behavior. Are we paying attention? Do we 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. And if the adult tries to initiate — by labeling an object that the baby didn't point at? Then there is no special learning effect (Lucca et al 2018).

So there's good reason to think that gestures affect learning. But the trick is to emphasize easy-to-decipher gestures.

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?

That's a reasonable question, given that baby signing programs feature signs that are non-iconic. Could the difficulty of learning such signs be a roadblock?

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 helpful 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).

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 as noted above, research suggests that many 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 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 counterproductive. 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.

Interested in gesture? You should be! Research suggests that gesture does more than help babies learn language. It can also help kids grasp mathematical concepts, and more. Read about it in this article.

References: Baby sign language

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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

image of mother holding gesturing, vocalizing baby by Lindsay Shaver/flickr

image of boy signing for more by Joe Szilagyi/flickr

image of mother in park reaching towards toddler by Bob B Brown/flickr

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


Original Article