Alun’s case above is a bit stranger than normal though as FAS generally manifests itself as a foreign sounding accent, not a change in actual language. The sufferers are people who haven’t been to the country that they now carry the accent for. It’s pretty strange isn’t it? This weird brain spaz has only affected about 60 people globally as far as official records are concerned. Below is the account of a lady who had super bad migraines and turned a bit Chinese:
https://www.youtube.com/watch?v=xvSdH0p2txw
The earliest recorded case of FAS dates back to 1907. In 1941 there is a famous account of a young woman in Norway who adopted a strong German accent thanks to shrapnel from an air raid. She was consequently shunned by society for the rest of her days. There’s also been a claim that George Michael, after waking from his pneumonia induced coma last year, had a west country accent for some time. I don’t think there’s any evidence of this but I would have liked to have heard him perform “Jesus to a child” sounding like a farmer. The next video shows Kay Russell who used to sound like she was from England, but now sounds like she’s Eastern European:
