Of the world's weirdest conditions, foreign accent syndrome (FAS) may trump the list. It is the only syndrome whose name accurately describes the disease. FAS is the sudden impulse for an individual to begin speaking in a foreign accent.

This syndrome has its origins in the not so distant past. In the 1940s, a Norwegian woman suffered a head injury from shrapnel during an air raid. After surviving the injury, the woman was left with what it seemed to be a German accent. Due to isolation, because of her German accent, she requested medical treatment.  

There are several factors that can lead to FAS such as, migraines, strokes, complications in brain surgery and complications with anesthesia that can lead to acute brain damage. Some researchers firmly associate FAS with a stroke or event that results in a traumatic brain injury. They believe the resulting damage affects the region of the brain responsible for speech and the coordination of muscles when speaking.

Individuals, who have experienced damage to their brain due to a stroke, may have experienced such acute damage where the only area affected controls vocal inflection.

Ted Lowenkopf, a neurologist and director of the Providence Stroke Center in Portland, Oregon stated other brain damage observed in diseases such as multiple sclerosis can also be a factor.

Researchers from Michigan State University believe that FAS is accompanied with a deficit in linguistic ability but does not affect an individual's prosodic expression (rhythm of speech or language expression such as surprise or sarcasm).  However, it will not suddenly make an individual bilingual. An individual suffering from FAS is more likely to produce speech of familiar dialects.   

Since the 1940s there have been approximately 100 cases of this condition around the world, including countries such as India, the United Kingdom, Canada and the United States. The most recent reported case of FAS was in 2011.