New research finds parents who frequently talk to toddlers not only help improve their child’s vocabulary, but they also give nonverbal abilities like reasoning and numerical understanding a boost.

A lot has been made of the 30 million word gap in the nearly 40 years since the original research was presented. The results established that children born in poverty hear, on average, 30 million fewer words by their third birthday than their more affluent peers.
The findings of the relatively small study have proven controversial over the years, with claims of racial bias and subsequent studies failing to replicate the results.
But one thing everyone involved seems to agree on is that the number of words a child hears in early childhood matters, with new research finding that the difference made may be even more significant than previously believed.
Researchers from the University of York have discovered that the number of words a child hears doesn’t just improve their vocabulary and linguistic development, it can also contribute to the development of nonverbal abilities like reasoning, numerical understanding, and shape awareness.
The study included 107 children, using audio recorders to document their daily lives over the course of three days.
What the researchers found was a positive association between cognitive abilities and the quality of adult speech children heard (based on both the number of words and lexical diversity).
The researchers acknowledged the need for further studies into the reasons behind this link, but it’s a link experts are not surprised to learn about.
Sara Piekarski, a speech-language pathologist in Tucson, Arizona, recently told Healthline that the link is, “absolutely accurate.”
She said, “When a child grows up in a language-rich environment, it shapes the way they understand, view, and use language. As parents, we lead by example, and our children naturally develop the same methods and use of language, even at a very young age.”
American Academy of Pediatrics (AAP) spokesperson and member of the executive committee of the Council on Early Childhood Dr. Dipesh Navsaria, agrees. But he cautions parents to consider that it may be more than just the number of words heard that make a difference.
“I think the observations researchers made are probably correct in the sense that there seems to be an increase in nonverbal abilities based on the number of adult words heard,” he told Healthline. “But I think what is very hard to control for in studies is not just the verbal interaction, but also the non-verbal interactions taking place.”
As he explains it, the number of words spoken may just be a proxy for the number of responsive and nurturing interactions taking place.
“It’s not really about the words, it’s about the interactions,” he explained. “If you have a parent who is mute, they can still have developmentally positive interactions with their kids. They shouldn’t think the lack of words is going to hold them back in any way.”
There is a wealth of research on the importance of these parent/child interactions on both cognitive development and behavioral outcomes.
Having a responsive, nurturing relationship with children can produce significant impacts on their overall development.
The researchers of this latest study acknowledge this as well, reporting that positive parenting (where parents were responsive and encouraging of exploration and expression) was associated with fewer signs of restlessness, aggression, and disobedience among the children studied.
So there may be more at play here than simply the number of words spoken. It could be that parents who are speaking to their children more are also more likely to be responding to, and engaging with, their children in a positive way.
“When parents are responsive and encouraging their kids to explore and express themselves,” Navsaria continued, “they are basically creating an environment where children know they are being heard and understand they have an ability to influence the attention of others in a positive way.”
The next question many parents reading this research may have is the importance of how they talk to their children.
For instance, there has been a fair amount of controversy surrounding baby talk over the years, with some experts advising against it and others advocating for any interaction that feels natural to a parent.
Piekarski said, “I have always talked to my own children with language that I would use with much older children and my peers. But, it’s just a personal preference, and honestly, how it comes naturally.”
She sees the positive benefits of this in her children, noting their higher level vocabulary starting at a young age. But she also stated that could just be part of the territory when it comes to having a speech-language pathologist as a mom.
Meanwhile, Navsaria falls firmly in the “whatever feels natural” camp.
“Parents should talk to their children in any way that feels comfortable for them,” he said. “I don’t think it’s a huge issue that I would say you must speak one way or another. Just go with what feels natural.”
He worries that in trying to over-coach how parents speak to their children, we may make parents too nervous about doing it “right.” And those interactions then become stilted and less beneficial overall.
Still, talking to little ones who don’t talk back can be uncomfortable for some parents.
To those parents, Piekarski suggested, “Narrate your life. It can be exhausting and over-stimulating, but I have always found that describing the world around us, asking open-ended questions, and reading books and asking questions about what you see and hear exponentially increases the quality of a child’s language development.”
If this feels uncomfortable to you, Piekarski says that’s okay. With time and practice, talking to your baby without the expectation of a response can become more natural. You’ll also begin to recognize the signs of engagement from your little one, even if they aren’t communicating verbally yet.
But those in-person interactions truly are what matter most.
Navsaria notes that the words a child hears from the television or radio don’t count.
“We have other studies that show those words don’t make a difference. The words need to come from live people in the environment who are interacting with the child in order to have an impact on development,” he explained.
He added, “There’s this saying, ‘screen time steals real time.’ Nothing your young child can watch on an app is truly educational, or as beneficial as the live interactions they can get from you. Even if it’s not harmful, what it’s doing is stealing that interaction time. And it’s those interactions that drive development.”
He summed it up by saying parents should remember, “There is no app to replace your lap.”
He encourages parents to emphasize turn-taking as kids get older, asking questions and giving them a chance to respond.
Navsaria wants parents to know it’s not just about barking words at your child, it’s about that reciprocal relationship taking place.
Piekarski agrees, noting that, “Making children notice their environment and express what they are seeing is a huge gift a parent can give.”