A British teenager who was in a nine-day coma woke up with an insatiable appetite for cheese and a love of cursing, his mother explained to the Daily Mail.

Kai Thomas, of Chesterfield, England, was a mild-mannered and polite 15-year-old who never used foul language, according to his mother Tracey Thomas. 

But ever since he awoke from a medically-induced coma after suffering bleeding in the brain last June he's been cursing up a storm- and consuming massive amounts of cheese. 

"One day I was in the kitchen, when I heard Kai yelling in his bedroom," Tracey Thomas said as she recalled one September incident. 

"He was screaming 'F***, b******, s***.' I wondered what on earth was going on - the expletives were coming thick and fast," she told the Daily Mail. 

Thomas walked into her son's room to find him munching on a block of cheese. 

"He had always liked cheese but now he was obsessed with it - he even added it to his cereal," Thomas said. 

Doctors were never able to determine exactly what caused Kai's brain to start bleeding in June 2014. He came home one day complaining of a headache and collapsed, the newspaper reported. 

Experts at Sheffield Children's Hospital "carried out scans and the results showed a bleed on the brain," Kai's mother said. "They told me it could have just come out the blue or he could have knocked himself."

After a six-hour surgery, doctors placed the teen in a medically induced coma to help him recover. He woke up nine days later unable to talk or move, side effects caused by the brain trauma he experienced. 

Kai eventually regained his speech and motor skills. Doctors said his sudden love for swearing is not unheard of. 

"'We asked the doctor about it and apparently it's quite normal for people to develop inappropriate or aggressive behavior after waking up from a coma."

His sudden love for cheese, however, remains a mystery.