Everything You Need to Know About Foreign Accent Syndrome How you can wake up with a different accent.

 -- What if you woke up one day suddenly speaking with a Southern twang or French lilt or British accent? In rare cases this happens to people when a brain injury leads to a rare condition called foreign accent syndrome (FAS).

Lisa Alamia, of Rosenberg, Texas, woke up from jaw surgery in December with an unexpected side effect: a new British accent. She has received nationwide attention for her rare FAS diagnosis.

"I was very shocked," Alamia told ABC News. "I didn't know how to take it. I was very confused. I said 'ya'll' all the time before the accent. Once I got the accent, I started noticing I'd say, 'You all."

The syndrome usually develops after neurological damage such as stroke. The syndrome means that a person's speech, specifically it's rhythm and tone, is affected. The sudden change in speech can signal a serious problem, according to medical literature. A change in speech in any way, including an accent change, can be the first sign of a stroke, and needs to be evaluated by a doctor immediately.

There are only about 100 documented cases of FAS, which was first described in 1907. A famous case involved a Norwegian woman shunned in her community when she developed a German accent after a traumatic brain injury during the Nazi occupation of Norway in World War II. A Scottish case published last month in Practical Neurology describes another instance of a woman who, like Alamia, developed FAS after a minor dental procedure, trading her Scottish accent for a German one.

Approximately 86 percent of cases are linked to neurological damage in the speech centers of the brain, from strokes, trauma, or other diseases like multiple sclerosis, according to a study published earlier this year in the journal Frontiers in Human Neuroscience. These patients usually don't take on a specific accent — for example, they don't have a true German accent — but the general changes in their prosody, or speech, can be mistaken for a specific foreigner.

A second type of FAS is not associated to any brain changes at all. These cases are often psychological in nature. For example, anxiety, depression, or emotional trauma can change aspects of how the brain interprets information and can cause someone to change their speech patterns, according to the Frontiers in Human Neuroscience journal. This can happen even though there is no physiological trauma to the brain that can be detected. However, this does not mean a patient is "faking it," it just means changes have happened in their brain on a subconscious level.

"It's such a rare condition that neurologists don't believe that this is a real condition," said Dr. Toby Yaltho of Houston Methodist Sugar Land Neurology Associates, who treated Alamia. "The big thing is to know that she's not faking it."

FAS can be treated in a variety of ways, from behavioral therapy to speech therapy to anti-anxiety medications, and some patients do recover their natural speech, according to medical literature.

Dr. Akshay Ganju is a resident in emergency medicine at Emory University in Atlanta. He is currently a resident in the ABC News Medical Unit.