Toddlers who are exposed to more screen time have fewer conversations with their parents or caregivers by an array of measures. They say less, hear less and have fewer back-and-forth exchanges with adults compared with children who spend less time in front of screens.

Those findings, published in the journal JAMA Pediatrics, make up one of the first sets of longitudinal evidence to confirm an intuitive reality: Screens are not just linked to higher rates of obesity, depression and hyperactivity among children; they also curb face-to-face interactions at home — with long-term implications that could be worrisome.

Researchers have long known that growing up in a language-rich environment is vital for early language development. More language exposure early in life is associated with social development, higher I.Q.s and even better brain function.

Given the value of such exposure, researchers were eager to investigate potential factors within the home environment that could be interrupting opportunities for parents to interact verbally with their children.

The researchers were particularly interested in three measures of language: words spoken by an adult, child vocalizations and turns in the conversation. They modeled each measure separately and adjusted the results for age, sex, and other factors, such as the mother’s education level and the number of children at home.

Researchers found that at almost all ages, increased screen time squelched conversation. When the children were 18 months old, each additional minute of screen time was associated with 1.3 fewer child vocalizations, for example, and when they were 2 years old, an additional minute was associated with 0.4 fewer turns in conversation.

The strongest negative associations emerged when the children were 3 years old — and were exposed to an average of 2 hours 52 minutes of screen time daily. At this age, just one additional minute of screen time was associated with 6.6 fewer adult words, 4.9 fewer child vocalizations and 1.1 fewer turns in conversation.

Dr. Perry, who studies language and social interaction among preschool children, said experts in the field should next investigate how media designed to be viewed by parents and children together “might allow for more conversational turn-taking and bypass some of the negatives of screen time.”

Sarah Kucker, an expert in language development and digital media at Southern Methodist University in Dallas who was also not involved in the study, called the analysis “impressive” but emphasized that understanding the nuances of how and when media is used in a larger and more diverse population is “a critical next step.”

“Media is not going away,” Dr. Kucker said, “but paying attention to how and when media is used may be a good future avenue.”