Cindy Langdon spent the weekend in bed. She felt nauseated, and the words tumbling out of her mouth had nothing to do with what she was...

KANSAS CITY, Mo. — Cindy Langdon spent the weekend in bed. She felt nauseated, and the words tumbling out of her mouth had nothing to do with what she was trying to say. It was frightening. And before the weekend was over, her son took her to the hospital.

Langdon, a healthy, active woman of 51, had had a stroke. And like many people who suffer strokes, her life since that weekend in May 2002 hasn’t been the same.

She doesn’t run for exercise anymore; her weakened right arm keeps her off the tennis court.

And — most puzzling to her and others — when she speaks, her voice sounds as if she comes from France. The accent is rather odd for a woman who grew up in Missouri. And it’s still a mystery even to scientists who have studied cases similar to Langdon’s.

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Langdon is among only a couple of dozen known cases of people who have developed “foreign accent syndrome.” In most cases, since the condition was identified more than 80 years ago, their natural voices have been altered by some kind of brain trauma or head injury.

People who know Langdon, including colleagues and marketing clients, have by now become accustomed to her change of voice. But when she meets new people, they often ask where she’s from.

“It’s annoying,” she says.

Before her stroke, most people knew Langdon as an effusive, creative woman. A divorced mother of three, she still operates a marketing, consulting and creative production firm out of her home.

In May 2002, Langdon says, she had two episodes that signaled something was wrong: Flashes in one eye, ringing in her left ear, poor coordination and difficulty speaking were among the symptoms. After the stroke, Langdon was unable to speak and underwent months of physical and speech therapy.

“All she could do was smile,” says daughter Morgan Langdon, now 24. “For someone who was active and very outspoken … to go from that to nothing but facial expressions, that was traumatic. We couldn’t fathom the idea that our mother could not speak.”

It took about six weeks before Langdon’s voice began to come back. A friend, Janis Rovick, remembers being in the room when Langdon looked up and said, “Hi.”

But then Langdon had to learn how to speak all over again.

“I knew the words,” she says now, “but I had to learn to form the words. There were some words I couldn’t say and sounds I couldn’t even make.”

Scientists who have studied patients with foreign-accent syndrome have begun to understand the condition better in recent years as brain-imaging technology has improved and as the Internet has made it easier to bring scattered research and researchers together, says Jack Ryalls of the University of Central Florida.

Ryalls has studied post-stroke speech problems for 25 years and saw his first case of foreign-accent syndrome 20 years ago.

While brain researchers used to think language involved discrete regions of the brain — part of the frontal lobe, for instance, in the left hemisphere — now they theorize it involves a network of neurons crossing and connecting multiple regions.

Foreign-accent syndrome may involve a lesion somewhere along that network, says Julius Fridriksson, assistant professor of communications sciences and disorders at the University of South Carolina.

The act of speaking involves the movement and coordination of 50 muscles, Fridriksson says, and damage along the nerve network could affect any movement controlling the larynx or face or other speech-related body parts.