Baby sign language: A guide for the science-minded

© 2009 Gwen Dewar, Ph.D., all rights reserved

Does baby sign language work?

Your 10-month old baby is crying. You ask her what she wants.

She lifts her hand in the air and squeezes her fingers shut—your family’s sign for milk.

Is this sort of communication really possible?

Research suggests that it is. In this article, I review the scientific basis for baby sign language. I address these questions:

• What is it?

• Why should parents use it?

• When can parents start?

• What’s the best way to begin?

As I note below, signing may have several advantages. In addition to the obvious advantage--you have an easier time understanding what your baby wants--it’s also possible that baby sign language could help strengthen attachment relationships.

And experimental research suggests that babies whose parents communicate with a combination of speech and gesture may develop larger spoken vocabularies.

But let’s start at the beginning. What do people mean when they say they are teaching their babies to sign?

Defining baby sign language: What is it?

Of course, you can teach your baby ASL if you want--just as you can teach your baby any other second language. Babies who are raised in bilingual environments take longer to master their first language. But they eventually catch up, and of course they grow up with the advantage of being fluent in more than one language.

But when people speak of research that supports the use of “baby sign language,” they are usually referring to something else. They are talking about encouraging babies to communicate with their hands. This includes

• Pointing at things of interest, and responding appropriately when babies point. (Example: When baby points at a cat, you say “That’s a cat!”)

• Actively teaching symbolic gestures--gestures that “stand for” something else (Example: To represent the concept of “food” or “eating,” you hold your fingers together, as if grasping something, and bring them to your lips)

• Responding to symbolic gestures that babies might invent (Example: Baby tugs at her shirt while she makes a questioning sound, meaning “Could you help me take off my shirt?”)

This isn’t real sign language. Real sign language has grammatical rules and a whole lexicon of abstract signs--symbolic gestures that bear no obvious connection to the things they stand for.

By contrast, baby signs are more transparent. It’s easier to guess what baby signs mean. And maybe that’s one reason why baby sign language is so helpful.

But it is helpful? Let’s consider the facts.

Why use “baby sign language?”

First of all, it’s important to keep in mind that gestures are a normal and natural part of language acquisition. In this sense, everybody is already using baby sign language.

For example, most babies will spontaneously begin pointing between 9 and 12 months. This is a major breakthrough in communication. The baby learns that she can make her wishes known by making eye contact and then shifting the direction of your gaze. By pointing, babies can make requests (i.e., “Give me that toy.”) They can also ask questions (“What is that?”) and make comments (“Look at that!”)

So pointing--and symbolic gestures, too--can help babies communicate without words. This has obvious, immediate benefits: It’s easier to figure out what your baby wants.

But there’s more to it. Studies suggest that babies form stronger attachments when their parents understand their interests, thoughts, and goals (Meins et al 2001).

And maybe gestures help babies expand their spoken vocabulary, too.

Babies who are encouraged to use gestures may find it easier to learn new words

Some is circumstantial. Meredith Rowe and her colleagues tracked a group of American babies from the age of 14 months. They found that the more a baby used gestures at 14 months, the bigger his spoken vocabulary was at 36 months (Rowe et al 2008). This relationship held even after adjusting for socioeconomic status and other background variables.

But the correlation between baby signs and spoken vocabulary might reflect general language ability. Babies who use more gestures might be more linguistically-inclined to begin with. As a result, they communicate better overall--whether by using baby sign language or spoken language.

Experiments can help clear this up. Psychologists Linda Acredolo and Susan Goodwyn have conducted a couple of experiments testing the effects of gesturing on language development.

In both studies, researchers asked a group of American parents to enhance their infant-directed speech with symbolic gestures (something that American speech tends to lack). The babies were tested at later points in their development and their language skills were compared with those of babies in control groups. Babies in the gesture groups showed better progress on some measures, like the size of a child’s receptive vocabulary (Acredolo and Goodwyn 1988; Goodwyn et al 2000).

This doesn’t mean that gesturing is always associated with bigger verbal vocabularies. A recent study of Italian kids—who use more symbolic gestures than American kids do—reported that signers had smaller spoken vocabularies (Iverson et al in press).

But there are theoretical reasons to believe that gestures would help babies learn speech.

As psychologists Jana Iverson and Susan Goldin-Meadow have noted, babies who gesture frequently might get better feedback from their parents (Iverson and Goldin-Meadow 2005).

For example, the baby who points at a new object might prompt his mother to label and discuss the new object. So the baby gets the information at just the right moment—when she is curious and attentive.

More broadly, experimental research suggests that kids learn and recall information better when they supplement their speech with gestures. (Click here for a review of this research and how it might explain the benefits of baby sign language).

It’s also possible that baby sign language motivates parents to speak more emphatically, with greater variations in pitch, and with greater emotion. Research suggests that this style of speaking--called “infant-directed speech” --helps babies learn to talk.

What about IQ?

When can I start?

Consider what we know about the timing of language acquisition.

Typical progress for spoken language acquisition

Between 7 and 10 months, most typically-developing babies begin syllabic babbling—repeating specific speech sounds, like “ba ba ba” or “ma ma ma” that are regularly used in their native language. Babies vary greatly in the timing of their first words. The average may be around 12 months. But some utter their first words well before that time, and others may take months longer (Oller 2000).

Typical progress for sign language acquisition

Babies born to deaf parents are exposed to real sign language from the very beginning. So when they start the equivalent of syllabic babbling, they do it with their hands.

Research suggests that “manual babbling” emerges around the same time as vocal babbling (Petitto and Marentette 1991). But the first signed words might appear earlier. A study of hearing babies born to deaf parents reported that babies made their first recognizable sign at an average age of 8.5 months (Bonvillian et al 1983). One baby signed as early as 5.5 months.

The implications

We should be cautious about interpreting these results, because the study was small and subject to sampling error. But even if these babies happened to be a particularly “fast” group, the results still tell us that some babies are ready to use signs at an early age.

Other research supports this view. One study tracked the infants of hearing parents from 6 to 24 months. Even at the beginning of the study, some babies were already using spontaneous gestures to communicate (Crais et al 2004).

And experiments suggest that very young babies are interested in dialogue. By 6 to 12 weeks old, babies are more likely to coo, smile, and move their hands when their parents make eye contact with them (Crown et al 2002). They also seem to like taking turns, waiting for their parents to stop talking before they begin with a “reply” (Bloom et al 1988).

This doesn’t mean you should start using baby sign language with your newborn. It takes months for babies to develop the motor control necessary to make hand signals.

But the research does suggest that even very young babies may pay attention to--and possibly learn about--your communicative gestures.

How do I begin?

In fact, Linda Acredolo’s research on baby sign language was inspired by the spontaneous signing of her baby daughter.

Acredolo and her baby were visiting a doctor’s office where there was a fish tank. When the baby saw the fish, she began puffing air out of her cheeks. Acredolo couldn’t figure out the connection until later that night, when she and the baby were engaged in their regular bedtime ritual of blowing on the fish toys that hung from a mobile above the crib (Acredolo and Goodwyn 1998).

So I think it makes sense to build on what your baby is already doing naturally. And then you can add your own gestures and signs. You might invent these yourself, or borrow ideas from somebody else’s baby sign language lexicon.

And keep in mind: Whenever you use a sign, be sure to speak the word(s) that go with it.

The idea isn’t to replace spoken language, but rather to supplement it. That’s what parents did in the experiments described above.

References: Baby sign language

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

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.

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

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

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.

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.

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