“When every time you open your mouth you hear [a] sound you don’t expect to hear… you almost feel like you are stuck in some sort of weird social experiment,” she added.

According to research done at linguistic institutes in the United States, the name Foreign Accent Syndrome, commonly abbreviated as FAS, is something of a misnomer.

In reality, FAS is a speech disorder that does not automatically give the victim a foreign accent, but rather leads to a drastic change in the way an individual produces his or her speech. These changes are then perceived by others as a “foreign” accent.

“It is an articulatory (speech output) problem that affects the rhythm or [intonation] of speech,” said Dr Sheila Blumstein, a professor of cognitive, linguistic and psychological sciences at Brown University.

The condition, first noted in 1907 by French neurologist Pierre Marie, has only around 60 recorded cases since its discovery.

Other notable cases include Kay Russell, another British woman who developed a French accent after suffering from migraines, Leanne Rowe, a Tasmanian woman who woke up sounding French after a car accident, and Judi Roberts, a New York native who developed what appears to be a British accent after suffering a stroke.

All of these victims acquired FAS after sustaining intense head pains or injuries, which is usually the genesis of the disease, according to research done by Dr Ashley Tran of the University of Arizona Medical Centre.

“In many cases of FAS the triggering event is a cerebral vascular event of some kind,” Tran said. “As for how exactly it manifests in the brain, it is difficult to say. The few cases [that have been reported] show various different locations of the brain affected… The pathophysiology behind FAS remains abysmally unclear.”

Despite the nebulous nature of FAS, one thing is certain – the “foreign” accents attributed to sufferers of the disease are largely defined by the perceptions and prejudices of listeners.

“Foreign Accent Syndrome is not an acquired dialect or foreign accent,” Blumstein wrote in a 2006 research paper. “[Instead], listeners are essentially being ‘fooled’ into attributing the sound pattern of their subjects to a foreign language or dialect.”

Chinese viewers commenting on the BBC One documentary of Sarah Colwill, which has been widely shared on Chinese social media services, prove this point.

“Is that really what a Chinese accent sounds like?” one member of China’s Sina Weibo online community wrote in response to the video. “I feel like it’s more Indian than anything else.”

“That is definitely not an authentic Chinese accent,” another wrote. “It’s obviously a Japanese one!”

Other posters were entranced by the idea of instantly acquiring foreign-sounding intonations.

“I wish I could one day have a perfect-sounding London accent,” one netizen from Shanghai remarked.

But while FAS may seem enticing to prospective English learners, actual sufferers of the condition have all expressed unease and difficulty in adjusting to their new way of speech, especially since there is currently no cure for the syndrome. In the case of Judi Roberts, the New Yorker who developed a British accent, she began using the pseudonym Tiffany Noel, rather than her real name. 

Meanwhile, Sarah Colwill's “Chinese accent” has kept her in speech therapy for months. Although she has since learned to accept her new voice, she still finds herself reminiscing for her old one from time to time. 

“It’s so hard to explain,” Colwill said in the documentary when reflecting on her condition. “It’s like somebody took a part of you away, and I’d just like to get that little bit back.”