Language Exposure and Speech Delay

Language exposure, the talk a child hears and joins in, is easy to picture as a count of words, but across many families stronger language goes with back-and-forth conversation, and with varied talk more than the sheer number of words heard. Neither a quieter home, two languages nor time in daycare is an established cause of speech delay.

What you’ll learn

• What the research ties to children’s language, and what it can’t explain
• What the evidence says about two languages, daycare and screens
• Small changes that turn ordinary talk into back-and-forth
• When a child’s talking is worth a closer look

Can Too Little Language Exposure Cause Speech Delay?

A quieter home is not among the established causes of speech delay. Studies that link home talk to children’s language are correlations, meaning they show what tends to go together across many families rather than what made any one child talk late, and when researchers have looked at late talking itself, the home explains only a small part of it.

Twin research published in Nature Neuroscience, covering over 3,000 sets of twins at age 2, found that the home the twins shared accounted for a large part of the ordinary differences in vocabulary across all the children, but only a small part among the children with language delay, where genes played the bigger role. A separate population study of 1,766 children found that parenting practices, parents’ mental health and the way a family functioned did not predict which toddlers were talking late at 24 months.

A small study from the babbling stage points the same way. In that study, described by the National Institute of Child Health and Human Development (NICHD), babies whose mothers answered their babbling moved on to more advanced babbling more quickly, yet the study’s author said the babies of less responsive mothers did not have significant language deficits.

So a quieter stretch, whether it comes from a hard year or from long working days, doesn’t belong on the list of known causes of speech delay, and time in daycare doesn’t either. Knowing what helps is meant for the months ahead, not for going back over the past, and there is more on what is and isn’t known to cause speech delay.

Back-And-Forth Versus the Number of Words Heard

A conversational turn is one round of back-and-forth, where an adult says something and the child answers, or the child starts and the adult answers, and the answer can be a sound, a word or a gesture.

In a study of 275 families published in Pediatrics, with children aged 2 months to 4 years, adult-child conversation was strongly linked to language development, and conversation explained part of the link between how much adults talked and how children’s language grew. The researchers concluded that parents should be encouraged to have two-sided conversations with their children, not only to read or tell stories to them.

Two reviews that pooled the results of many studies add to the picture. One, in Child Development, found that the variety of words and the complexity of sentences children hear were more strongly linked to their language than the sheer amount of talk. The other, covering 37 studies in Pediatrics, found that sensitive responsiveness, meaning noticing a child’s signals and answering them, was linked to children’s language more strongly than parental warmth was.

Researchers writing in Child Development have described the vital ingredient as good-quality talk directed to a child, rather than talk a child overhears, and early language is carried by shared attention, the moments when toddler and adult are both absorbed in one thing. None of these studies sets a number of words a child should hear each day.

From clinical practice

Talking enough is a worry attentive parents carry, as if a child’s language depended on reaching some number of words a day.

The studies keep returning to something else: the back-and-forth, turns taken together about something the child and the adult are both looking at. The child offers a sound, a word or a point, and the adult answers. A few exchanges like that, over something the child has noticed, sit closer to what the research describes than a long stretch of talk the child only hears.

Two Languages at Home

A second language at home is not a cause of speech delay. Late talking is not a result of introducing a second language or of learning two at once, as the American Speech-Language-Hearing Association (ASHA) states, and the American Academy of Pediatrics (AAP) says that learning more than one language does not cause or worsen speech or language delays.

Counting is where two languages can mislead, because a bilingual toddler’s words are spread across both, so a tally in one language leaves part of the vocabulary out. Once the words in both are added together, bilingual children hit their milestones on the same schedule as children learning a single language, and the AAP’s parent advice is to count words in both. ASHA notes that mixing the two languages in one sentence is an ordinary part of learning more than one.

ASHA’s advice to families is to talk with a child in whichever language or languages they are most comfortable using, which will not confuse the child or cause or worsen a speech or language problem. ASHA also says that raising a child in one language only is not necessary and should not be advised as a response to late talking, so a family worried about speech has no reason to give up a home language.

Screens, Background TV and Video Calls

Research has not shown that screens cause speech delay, although more viewing goes with somewhat lower language skills across groups of children. A meta-analysis of 42 studies covering 18,905 children, published in JAMA Pediatrics, found small links between lower language skills and both longer hours of screen use and a television left on in the background, while educational programs, watching together with an adult and starting screen use later all went with stronger language skills.

A study of 220 families, also in JAMA Pediatrics, found that at 36 months each extra minute of screen time went with fewer words from adults, fewer sounds and words from the child and fewer conversational turns. That fits the likeliest explanation for the link, which is the conversation that doesn’t take place during viewing, and one episode on a difficult afternoon is a long way from hours of viewing.

The AAP says children younger than 2 learn best from exploring the world around them and playing with other children and adults. Video calls with family are treated differently from other screen time. The Centers for Disease Control and Prevention, or CDC, suggests keeping screen time for babies and young toddlers to video calls with loved ones, and the AAP suggests that during a call an adult explains who is on the screen, repeats what they are saying and describes what is happening.

Everyday Habits That Invite a Child to Answer

The habits that build back-and-forth fit into an ordinary day and need no special toys. The AAP’s parent advice is to spend plenty of time playing with, reading to and talking with an infant or toddler, and the CDC’s suggestions are the same everyday activities of talking, reading, singing and naming things. A few small changes make that talk more two-sided:

• Talk back to babbling. The CDC suggests smiling and talking to a 4-month-old when the baby makes sounds, because it teaches a baby to take turns, and NICHD notes that answering a baby’s sounds shows the baby they are heard.
• Pause so there is room for a reply. NICHD advises talking to babies and then pausing to let them answer, which helps them learn how a conversation flows.
• Repeat what your child says, then add a little. The CDC’s example for a toddler around 15 months is to answer “ba” with “Ball, yes, that’s a ball.” ASHA lists copying and adding to a child’s words or actions among the interaction styles that support language.
• Reply to what your child is trying to tell you. ASHA also counts responses tied directly to a child’s attempt to communicate, whether that is a word, a sound or a point.

Books and songs fit the same pattern, since reading together is one of the activities both the AAP and the CDC recommend, and a book turns two-sided as soon as the child points and the adult answers. There are more ideas for helping a toddler talk.

If Your Child’s Talking Still Worries You

Talk at home helps a child whatever else is going on, but it is no test of whether a child needs a look from someone qualified. If a two-year-old says fewer than 50 words, that alone is reason to ask, and using 50 or more words, along with combining two words, appears on ASHA’s list of communication milestones for 19 to 24 months.

A hearing check comes first for almost any speech concern, as the AAP advises. A parent can also contact the state’s early intervention program directly, without a doctor’s referral, for an evaluation that is paid for publicly under Part C of the federal Individuals with Disabilities Education Act (IDEA). There is more on what speech delay means, and on how talking grows through the early years in speech and language development.

Common Questions From Parents

How Many Words Should I Be Saying to My Baby Each Day?

Neither the American Academy of Pediatrics nor the CDC sets a daily number. Both recommend everyday talking, reading, singing and play, and a study of 275 families in Pediatrics tied children’s language strongly to back-and-forth conversation.

Does Speaking Two Languages at Home Cause a Speech Delay?

No. ASHA says late talking does not come from learning a second language, and the American Academy of Pediatrics agrees. Count the words your child knows in both languages together, and keep using whichever language your family is most comfortable in.

Does TV Count as Talking to My Child?

Not in the way conversation does, because a show cannot answer your child. The American Academy of Pediatrics says children under 2 learn best from exploring and from play with other children and adults, and in a large review, co-viewing went with stronger language skills.

Can Daycare Affect My Child’s Speech?

Time in daycare has not been found to cause speech delay, and neither has having both parents at work. Back-and-forth supports language wherever it happens, whether with a parent at home or with a caregiver who answers a child’s sounds, words and points during the day.

Is Narrating My Day to My Toddler Enough?

It helps, because narrating is talk aimed at your toddler, which counts for more than talk a child only overhears. Narration becomes conversation when it follows what your toddler is doing and leaves pauses for a sound, a word or a point in reply.

Do Quiet Parents Raise Late Talkers?

The research on late talking points away from that. Twin research found the shared home explained only a small part of language delay, and a population study found late talking at 24 months unrelated to parenting practices. More back-and-forth still helps, from any starting point.

Reviewed by Monica d’Errico-Franklin, M.S., CCC-SLP

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