The scientific evidence on baby sign language is mixed, which often surprises parents expecting a clear yes or no answer. While some recent studies show cognitive advantages and literacy benefits for infants exposed to sign language, other research finds that signing doesn’t actually accelerate overall language development compared to spoken language alone. What is clear from the current research is that learning sign language does not harm spoken language development—a finding that should reassure any family considering introducing signs to their hearing children.
Parents often ask this question because they want to make the best choice for their child’s development. The answer depends partly on what you’re measuring: research shows that sign language can support visual processing and concept formation in very young infants, may boost certain cognitive measures, and strengthens foundational literacy skills. But if you’re hoping signs will speed up your child’s language development beyond what they’d achieve with spoken language alone, the evidence doesn’t consistently support that. This article explores the actual research, what it means, where studies disagree, and what families should realistically expect from baby sign language.
Table of Contents
- What Does Current Research Actually Show About Baby Sign Language?
- The Cognitive Development Question—Does Sign Language Create a Brain Advantage?
- Language Development Speed—Why Don’t Signs Speed Up Overall Communication?
- Will Sign Language Interfere With Spoken Language Development?
- Literacy Benefits—Where Sign Language Shows Clearest Promise
- Age-Related Differences in Sign Language Exposure
- The Research Gap and What This Means for Families
- Conclusion
What Does Current Research Actually Show About Baby Sign Language?
The scientific picture is genuinely divided. A 2012 study published in ScienceDaily concluded that signing in babies does not accelerate language development—children who learned baby sign developed language at similar rates to children who didn’t. This finding was echoed by Kirk and colleagues, whose critical review found no significant advantages for children who participated in baby sign programs compared to control groups. These studies suggest that if your goal is to boost your child’s language development trajectory, signing alone won’t necessarily do that. However, other research points to specific benefits in different areas.
Northwestern University researchers found in 2021 that sign language supports infant cognitive development in hearing infants aged 3-4 months, offering advantages in how babies form object categories and link language to cognition. A 2025 study highlighted in the Indiana University Literacy Blog found that two-year-old children exposed to baby sign scored 12 points higher on the Wechsler Intelligence Scale for Children compared to control groups—a measurable difference, though researchers continue studying whether this advantage persists over time. The discrepancy between these findings matters: some studies measure language speed and find no difference, while others measure cognitive or literacy-related skills and find advantages. A 2026 study published in SAGE Journals is examining baby sign programs paired with spoken words and their impact on vocabulary development, with results still being analyzed in detail. The takeaway is that “no acceleration in language speed” doesn’t mean “no benefits at all”—the benefits just appear in different cognitive areas.
The Cognitive Development Question—Does Sign Language Create a Brain Advantage?
The Northwestern research on 3-4 month old infants is one of the most compelling findings in this debate. Researchers discovered that infants exposed to sign language showed advantages in how they categorized objects visually and linked language concepts to cognition, whether that language was spoken or signed. This suggests something interesting: the brain benefits from language exposure itself, and the mode (spoken vs. signed) may matter less than we assume for very young infants processing visual information. However, if cognitive advantages exist, they appear to be context-dependent.
The 12-point IQ difference found in two-year-olds who learned baby sign is interesting, but researchers caution that this doesn’t mean every child exposed to signs will show this result. Individual variation is huge, and a family’s overall engagement with language—whether signed, spoken, or both—likely matters more than signing alone. Additionally, these studies typically involve families actively teaching baby signs, which means these children are getting extra language interaction of any kind, not just access to signs specifically. A limitation to consider: most studies of cognitive advantages track children for relatively short periods. Long-term follow-up studies that track these children into school age are less common, making it unclear whether early cognitive boosts translate into sustained advantages. For families drawn to signing primarily for IQ gains, the evidence is promising but not definitive—the more reliable benefit is that signing doesn’t harm development while potentially offering cognitive practice.
Language Development Speed—Why Don’t Signs Speed Up Overall Communication?
This is where the clearest evidence emerges: baby sign doesn’t accelerate overall language development. The 2012 research and Kirk’s critical review are consistent on this point—children exposed to baby signs reach language milestones (first words, combining words, etc.) at similar ages as children without sign exposure. For some families, this is disappointing; for others, it reframes what signing is for. The reason is probably straightforward: babies are remarkably efficient at language acquisition regardless of the modality. A hearing child exposed to spoken language will reach language milestones around the same time whether or not they also see signs.
Research published in the Journal of Speech, Language, and Hearing Research in 2022 reinforces this by confirming that learning a sign language does not hinder acquisition of a spoken language. In fact, bilingual language development—including spoken-sign bilinguals—follows similar developmental timelines to monolingual development. The practical implication: if you’re introducing signs to accelerate your baby’s ability to communicate, evidence suggests signs won’t give you that advantage. But if you’re introducing signs for other reasons—to honor Deaf culture, to give your child visual language exposure, to reduce frustration during the pre-verbal period, or because sign is a family language—the research shows your child won’t fall behind. They’ll simply develop both languages on a typical timeline.
Will Sign Language Interfere With Spoken Language Development?
This is perhaps the most important question for hearing families, and the evidence is reassuring: no, learning sign language does not harm spoken language development. The 2022 JSLHR study published by the American Speech-Language-Hearing Association explicitly examined this and found no interference. Children who are bilingual in spoken and sign languages develop both languages normally, just as children who are bilingual in two spoken languages typically do. One practical consideration: interference might occur if a child receives sign language exclusively and doesn’t get adequate spoken language input, but that’s not a limitation of signing itself—it’s a limitation of single-language exposure. A hearing child with hearing parents who signs and speaks has access to both.
A hearing child with Deaf parents who signs and is exposed to spoken language through relatives, school, media, or community also develops both. The key variable isn’t the presence of signs; it’s the presence of adequate input in both languages. Some families worry that dividing attention between two languages slows development in both, but this is a common misconception not supported by research. Bilingual children often show slightly different vocabularies in each language (smaller in each individually, larger when combined) but reach overall communication milestones on typical timelines. For sign and speech specifically, research confirms that a hearing child won’t choose one language and abandon the other—they’ll typically use each language in contexts where it makes sense.
Literacy Benefits—Where Sign Language Shows Clearest Promise
One area where sign language shows consistent research support is literacy development. Research from Michigan State University confirms that learning signs fosters vocabulary, syntax, and language structure—the exact foundational elements that support reading comprehension. This connection makes linguistic sense: learning any language, signed or spoken, strengthens understanding of how language works conceptually, and that understanding transfers to literacy. The mechanism appears to be that sign language, with its visual-spatial grammar, engages different cognitive systems than spoken language while still teaching core linguistic principles. A child who understands how signs combine to create meaning, how sign order matters, and how sign modifiers work is simultaneously learning abstract linguistic principles that apply to reading.
The 12-point Wechsler advantage mentioned earlier may partly reflect this literacy foundation advantage, as those tests include verbal and language-related components. However, this benefit isn’t unique to sign language—learning any second language, including spoken languages, also supports literacy development. The advantage of sign specifically is that it may engage visual processing systems that complement spoken language learning. For families focused on supporting their child’s reading skills, sign language is one valid tool among others (reading aloud, wordplay, writing), but it’s not a shortcut. It’s a legitimate contributor to linguistic foundation building.
Age-Related Differences in Sign Language Exposure
The Northwestern research specifically highlighted 3-4 month old infants as showing cognitive benefits from sign exposure. This raises a question: does timing matter? The research suggests it might, though most studies don’t isolate age effects precisely. Early sign exposure appears to support very young infants’ visual processing and concept formation, potentially because their brains are primed to absorb any language input at that age.
For older infants and toddlers, benefits may shift. The 2025 study showing IQ advantages involved two-year-olds, suggesting sign language continues to offer cognitive benefits even after the infancy period. However, research at different age points isn’t always directly comparable, making it hard to say definitively whether starting at 3 months versus 12 months produces different long-term outcomes. For practical purposes, families should know that sign language exposure can be beneficial at any age, though the specific cognitive pathways may differ.
The Research Gap and What This Means for Families
A significant limitation of current research is that most studies are relatively short-term, tracking children for months or a few years. Long-term follow-up studies that track sign-exposed children into school age and beyond are less common, leaving questions about whether early advantages persist, fade, or shift over time. This gap matters because a 12-point IQ difference at age two might look different at age five or ten.
Additionally, recent research like the 2026 SAGE Journals study on baby sign paired with spoken words is still being analyzed, and future research may shift our understanding. The evidence base is growing, particularly for literacy benefits and cognitive advantages in specific domains. For families making decisions now, the prudent approach is to base choices on current evidence—sign language does no harm and offers potential cognitive and literacy benefits—while staying flexible as research evolves and remaining aware that claims of dramatic acceleration or transformation are not well supported.
Conclusion
Baby sign language is scientifically proven to be safe and potentially beneficial, but not in the way some promotional materials suggest. The evidence shows that signing doesn’t harm spoken language development and may offer cognitive advantages in visual processing, concept formation, and literacy foundations. However, signing does not accelerate overall language development beyond what a child would achieve with spoken language alone, and families shouldn’t expect their child to communicate earlier just because they’re exposed to signs.
The most honest scientific summary is that signing is a legitimate language choice with real research support—just not a magic acceleration tool. If your family signs for cultural reasons, to support a Deaf relative, to reduce frustration during the pre-verbal period, or because you want your child bilingual, current research supports that choice. The science says your child will thrive, develop language typically, and potentially build stronger literacy foundations. That’s evidence-based—and real.