Are Twins More Likely to Have Language Delays?
Written by Kelly Schott, Speech-Language Pathologist at Babbly
Twin births are on the rise. In 2020, twins accounted for 3.2% of births in the United States compared to 1.9% of births in 1980. If you’re a parent of twins, you might already know that they have a higher likelihood of speech delay compared to their non-twin peers. And, you’ve likely heard a lot of theories about why that might be. The truth is that there are lots of myths about twins and speech development—but most aren’t actually grounded in science. In this article, we’ll take a look at the latest research for twins born after 30 weeks gestational age and separate fact from fiction. When parents, teachers and healthcare providers have a better understanding of early speech and language milestones in twins, they’re better able to support their overall development.
Early Language Development In Twins
By 24 months, children are usually demonstrating their growing vocabularies and producing two-word combinations. New research suggests that 24-month-old twins are more likely to have a smaller vocabulary and produce fewer grammatical markers and word combinations than non-twins—something researchers call the “twinning effect.” But it’s important to note that this difference in vocabulary isn’t permanent: twins usually catch up to non-twins with time.
Researchers note that twins’ language growth improved with age, often catching up to their single-born peers over time. In fact, twins perform only slightly lower than their single-born peers on vocabulary tests at age three and show no significant difference in expressive language by age five. And, teachers don’t report any noteworthy differences in expressive language skills between twins and their single-born peers by age five.
While most twins’ vocabularies tend to catch up to their single-born peers by early school-age years, twins are more likely to score lower on standardized tests for speech sound development or articulation skills at age six. Researchers suggest that twins may master later-developing speech sounds at a slower rate than single-born peers. That means that twins’ speech may be harder to understand or less clear and they may have difficulty with later developing speech sounds, such as “r” and “th.” That said, there is a lot of variability in early language and speech sound acquisition for all children—and not every twin demonstrates a speech and language delay.
What Risk Factors Contribute to Language Delays in Twins?
The myth that twins may have delayed language development because parents are splitting their attention between two toddlers is just that: a myth. Here’s what the research says about risk factors that can contribute to speech and language delays: Twins born after shorter gestations or with lower birth weights are more likely to be delayed in expressive language and have smaller vocabulary sizes at three years of age. And, identical twins are more likely to have language delays than fraternal twins.
How Can I Help My Twin’s Language Development?
Reinforce each child’s communication attempts by imitating their early vocalizations or babbling. As your twins grow, you can give them individual praise for following directions or answering a question. Tip: Use language specific to each child by using their name often.
Take advantage of opportunities to practice the activities above with your twins individually when two caregivers are present to reinforce each child’s unique communication style.
Enroll your twins in preschool: Researchers hypothesize that twins’ language skills typically catch up to their single-born peers before age five, as preschool attendance before this time often correlates with improved expressive language and social language skills.
If you are concerned about your twin’s language development or would like to learn more about their unique language development, reach out to one of our Speech-Language Pathologists for information and personalized activities to support their development journey.
Other parents are asking about:
Are premature babies at risk of language delay?
Are boys more likely to talk later than girls?
References:
Culloty, A. M., O'Toole, C., & Gibbon, F. E. (2019). Longitudinal study of expressive language and speech of twins at 3 and 5 years: outgrowing a twinning effect. Journal of Speech, Language, and Hearing Research, 62(7), 2425-2437.
Michas, Frédéric (2020). Birth rate for twins in the United States from 1980 to 2020 (per 1,000 live births). statista. https://www.statista.com/statistics/276017/us-twin-birth-rate/
Rice, M. L., Zubrick, S. R., Taylor, C. L., Gayán, J., & Bontempo, D. E. (2014). Late language emergence in 24-month-old twins: Heritable and increased risk for late language emergence in twins. Journal of Speech, Language, and Hearing Research, 57(3), 917–928.
Rice, M. L., Zubrick, S. R., Taylor, C. L., Hoffman, L., & Gayán, J. (2018). Longitudinal study of language and speech of twins at 4 and 6 years: Twinning effects decrease, zygosity effects disappear, and heritability increases. Journal of Speech, Language, and Hearing Research, 61(1), 1–15.