Jane Beard and Jeffrey Davis didn’t realize how little they speak to their children by phone until they called AT&T to switch plans. The Silver Spring, Md., couple had accumulated 28,700 unused minutes.

“None of the kids call us back! They will not call you back,” said Beard, a former actress who with her husband coaches business leaders on public speaking.

A generation of e-mailing, followed by an explosion in texting, has pushed the telephone conversation into serious decline, creating new tensions between baby boomers and those in their teens, 20s and early 30s.

Nearly all age groups are spending less time talking on the phone; boomers in their mid-50s and early 60s are the only ones still yakking as they did when Ma Bell was America’s communications queen. But the fall of the call is driven by 18- to 34-year-olds, whose average monthly voice minutes have plunged from about 1,200 to 900 in the past two years, according to research by Nielsen. Texting among 18- to 24-year-olds has more than doubled in the same period, from an average of 600 messages a month two years ago to more than 1,400 texts a month, according to Nielsen.

Young people say they avoid voice calls because the immediacy of a phone call strips them of the control that they have over texting, e-mailing, Facebooking or tweeting. They even complain that phone calls are by their nature impolite, more of an interruption than the blip of an arriving text.

Kevin Loker, 20, a junior at George Mason University, in Fairfax, Va., said he and his school friends rarely just call someone for fear of being seen as rude or intrusive. First, they text to make an appointment to talk. “They’ll write, ‘Can I call you at such-and-such time?’ ” said Loker, executive editor of Connect2Mason.com, a student media site.

The bias against unexpected phone calls stems in good part from the way texting and e-mail have conditioned young people to be cautious about how they communicate when they are not face to face, experts say.

Deborah Tannen, a linguistics professor at Georgetown University who studies how people converse in everyday life, said older generations misinterpret the way younger people use their cell phones.

“One student told me that it takes her days to call her parents back and the parents thought she was intentionally putting them off,” she said. “But the parents didn’t get it. It’s the medium. With e-mails, you’re at the computer, writing a paper; with phone calls, it’s a dedicated block of time.”

Tannen, 65, worries that texting may fall victim one day to the same neglect that phone calls now face. Her generation’s feelings, she said, are perfectly captured in a recent New Yorker magazine cartoon that shows two older, balding men sitting at a bar. The caption reads: “I used to call people, then I got into e-mailing, then texting, and now I just ignore everyone.”

Not only are people making fewer calls, but they are also having shorter conversations when they do call. The average length of a cellphone call has dropped from 2.38 minutes in 1993 to 1.81 minutes in 2009, according to industry data. And between 2005 and 2009, as the number of minutes Americans spent talking on cellphones inched up, the number of cellphone messages containing text or multimedia content ballooned by 1,840 percent.

Land lines are disappearing. Verizon, the nation’s second-largest land line carrier behind AT&T, says its hard-wired phone connections have dropped from 50 million in 2005 to 31 million this year.

“Here’s the issue: We don’t want to talk with each other most of the time,” said Naomi Baron, an American University linguistics professor who published a paper in June called “Control Freaks,” dissecting how Americans communicate online and on mobile devices.

Lianna Levine Reisner, 26, a development director at a nonprofit group, said her peers have phone gripes of their own about their elders.

Reisner said her parents intrude on her day with questions that they deem urgent but that in her reality are not.

“My dad calls asking me about the details of my travel plans, and they’re not in my head, they’re in some e-mail, so I say, ‘I will e-mail you everything,’ ” she said. “I know my parents are offended. I’ve asked my mom not to call me during the work day if it’s just to chat. We came to an agreement. I know she felt bad. She wanted to feel connected to me.”