Experts Explain Natalie Portman's Weird Voice in the New Jackie O Biopic

Depending on the viewer, Portman's vocal choices could sound brilliant or campy. She speaks in a slow cadence, with pauses and occasional Long Island twang. She sounds a bit like Padmé Amidala, Portman's character in Star Wars, if she was raised by Kennedy Onassis's cousin, Edith Beale, of Grey Gardens fame. Since Kennedy Onassis turned down most interviewers—even Oprah and Barbara Walters—her voice remains a mystery to younger views. Does Portman sound strange, or is she simply imitating an uncanny woman?

"Natalie clearly worked diligently with original clips of Jackie herself and a dialect coach to translate Jackie's sounds into her mouth, in terms of the quality and intonations, as well as the vowel and consonant sounds," says Samara Bay, a dialog coach to actors like Aaron Eckhart and the cast of the movie Loving.

The First Lady's voice stems more from her wealth than her hometown. "Anyone's accent is a composite of influences, and while geography is certainly chief on that list, it is also a product of the way people from that area spoke during the decades depicted," explains New York-based vocal coach John West. Portman shows traces of what is commonly called a "Mid-Atlantic dialect." The accent has faded from popular use, but, according to West, it was popular in 20th century among wealthy families, because teachers taught girls the speaking style in boarding schools.

One Kennedy Onassis expert believes she amplified her Mid-Atlantic voice. Ron Galella, the photographer that TIME called "King of the Paparazzi," made his name shooting candid images of the First Lady. He spent years photographing her in the 1960s and 1970s, but she only spoke to him a few times. According to Galella, he spotted the First Lady outside the 21 Club, where she was reportedly eating with her second husband, Aristotle Onassis. She grabbed his wrist, pinned him against her limousine, and said, "You've been hunting me for three months now."

"She [had] a whispery Marilyn Monroe voice, very low pitch, baby like," Galella says in a phone interview.

In real life, Galella remembers Kennedy Onassis lacking the makeup and fancy clothes that cemented her reputation as America's most stylish first lady. His most famous image, Windblown Jackie, which is in the Museum of Modern Art's collection, shows Kennedy Onassis with a bare face and tousled hair. He believes she morphed her voice, and spoke infrequently, to develop a specific public image that matched her famous fashion style.

"I think [Kennedy Onassis] was a great actress," he says. "She developed all these public faces where she was whispery and was very aloof and didn't speak much. She created a mystery, which creates glamour."

To create Kennedy Onassis's public voice, West advises dropping R's at the end of words and modifying certain vowels. He also recommends loosening the vocal cords, for a "breathy" effect similar to the voice of Paris Hilton. On a film set, Bay expects an actor would rely on instincts while also following a sound change sheet. "[The coach gives] a list of substitutions from one sound to another," she explains. "It's exacting."

Of course, it's impossible for any actor to perfectly replicate a voice, let alone the voice of a very specific First Lady. As Bay says, "Every voice sounds a little different from every other because every instrument is a little different, by which I mean our actual anatomy."