While the upcoming Netflix drama series “Kennedy” will chronicle the famous political dynasty from 1931 to 1944, the family’s signature Boston accent won’t be so pervasive.

Nick Robinson, who plays Joe Kennedy Jr., JFK’s older brother who was originally being groomed for the White House before he was killed in action during World War II, tells me, “We made the executive decision beforehand that we’re going to steer away from the Boston accent. So it’s subtle. Also, that accent has sort of changed over the years. It was initially like this mid-Atlantic upper-class accent and then it sort of changed to [what] I feel modern audiences associated more with working class Boston.”

Preparing for the role proved to be a history lesson for Robinson. “I knew about the Kennedy family, but I didn’t know much about Joseph Kennedy Jr., so that was a fun time to get a deep dive onto him and his life and his legacy,” he said at the recent premiere of his new Netflix rom-com “Voicemails for Isabelle.”

Laura Donnelly, who plays matriarch Rose in the eight-episode “Kennedy,” says she and Michael Fassbender, who plays patriarch Joe Sr., had prepared to use the couple’s accents before filming began. “Once Michael and I had arrived on set, we’d already decided that we’d already done our work on the accents,” Donnelly told me at recent “Sugar” Season 2 premiere in Los Angeles. “Then we found out that the general vibe was going to be pull it back. We were a bit like, ‘Oh, I don’t know who to do that.’”

Not that they were asked to lose the accents all together. “Their accent was kind of created in a very aspirational way, and so you do have to have that reference,” Donnelly said. “At the same time they had nine children. We didn’t want these tiny kids trying to do that accent, so there had to be a way of closing that gap so the kids would be more of a general and that Michael and I would do the more distinctive accents. I think that kind of creates a blend.”

The series is based on Fredrik Logevall’s book “JFK: Coming of Age in the American Century, 1917-1956.”

Donnelly also talked about the pressure of taking on the role of the iconic matriarch. “I think that it’s actually very lucky for me that I’m not American and I didn’t feel age-old pressure of we know so much about them,” said Donnelly, who is Irish.

She continued, “So pressure like that, I try and just generally shut out and I’m like I’m playing a real woman.”

Donnelly’s preparation included watching footage of Rose being interviewed later in life. Rose died in 1995 at age 104. “I’ve come to admire her so much,” she said. “Oh, my goodness, what she endured and with such dignity and grace.”