What is Foreign Accent Syndrome?

So here is the official definition of FAS as per Wikapedia:

Foreign Accent Syndrome is an unusual psychological disorder which, in its milder form, causes people it affects to pronounce words in a foreign accent. The disorder usually follows a brain injury caused by non-perforating head trauma, as perforating head trauma is much too gory for a proper mental ilness. In extreme cases, victims of Foreign Accent Syndrome can actually acquire knowledge of the foreign language associated with their new accent, slang terms and humorous exaggerated versions of national stereotypes included. A victim who develops a Lithuanian accent might acquire the Lithuanian language, tell other people to "Laizhyk asilo shikna", piss on bottles of Švyturys Ekstra, and date his sister. As of the present, there is no known cure or treatment for Foreign Accent Syndrome, and scientists have still been unable to completely unravel how the disorder works. People afflicted with the disorder are usually shunned in their community, and turned into social pariahs. Fortunately, there are government sponsored programs that let victims of FAS assimilate in foreign countries where their accents are accepted.

The History of FAS:

The first confirmed case of Foreign Accent Syndrome occurred on 09 August 1917, when 16 year old Kentucky resident Amelia Clementine, after a mild domestic quarrel and subsequent coma, woke up with a strong English Accent. Her friends and family were initially baffled by her mysterious ailment, and thought that she was afflicted with a "devil disease" and should be "put to death with a stick". Note that up until the 1940's, the relationship between America and England was a feeling of mutual animosity, and that death by large stick was a culturally acceptable practice in backward Kentucky towns. Amelia's parents did not initially accept the mysterious changes happening to her, and were shocked to learn that she used British English instead of American English; many of her relatives were confused of her tendency to use the irregular forms of past tenses and past participles (spoilt rather than spoilled), rather than the regular forms.^[1]