'Foreign accent syndrome' has caused a New Zealander, Ronwyn Fox, a resident of Invercargill, who has never been to Britain, to speak in a mixture of Welsh, Scottish, and North London accents.
"I am a third-generation New Zealander and my mother and father didn't have a British accent. Nor does anyone I know," Fox said.
Fox has suffered from multiple sclerosis for 25 years.
"It happened overnight. My eyesight suddenly went and my voice changed at the same time," The Telegraph quoted Fox as saying.
"People ask me where I come from. It's very hard for them to understand the accent is coming from inside my head," she added.
An MRI scan showed that two lesions had developed at the back of her brain.
According to Fox a doctor at Invercargill Hospital told her that the lesions were the most likely to change her speech.
"It certainly surprised me. My family has grown used to it now but the worst thing is friends I haven't seen for a long time," she said.
"If they ring up they don't believe it's me on the phone. My best friend from Christchurch hung up," she added.
Despite her Welsh first name, Fox draws her ancestry to the Orkney Islands and England.
"It doesn't worry us. In fact it can brighten up a boring day," her husband said.