An American cancer patient has developed a permanent Irish accent.

Researchers have reported an unusual medical oddity where an American cancer patient in his 50s developed an uncontrollable Irish accent, potentially due to a paraneoplastic neurological disorder triggered by his immune system. The patient was undergoing treatment for prostate cancer at Duke University in Durham, NC when he suddenly began speaking in an Irish brogue accent for the first time in his life. The case was reported in the January issue of BMJ Case Reports.

According to the report, the man’s accent was present in all settings and gradually became persistent. Despite having never lived in Ireland or traveled to the country, the man developed the speech pattern approximately two years after being diagnosed with a metastatic hormone-sensitive prostate cancer. The patient developed a case of foreign accent syndrome (FAS), a rare speech disorder characterized by a consistent change in speech that presents as a foreign accent.

The report, which was co-authored by researchers from Carolina Urologic Research Center in South Carolina, noted that the patient had no history of psychiatric disease before developing the Irish accent. However, the patient had briefly lived in England and had Irish friends and family members, which may have contributed to his familiarity with the accent.

The doctors explained that the most likely cause of the speech shift was a paraneoplastic neurological disorder. The patient’s immune system, while fighting cancer, likely attacked parts of his brain, spinal cord, peripheral nerves, or muscles, causing FAS. As a result of the disorder, the patient developed paralysis in his legs and arms, which is a sign of paraneoplastic syndrome. Despite medical intervention, the patient eventually passed away.

According to the report, this is the first case of FAS described in a patient with prostate cancer and the third described in a patient with malignancy. In previous research, FAS has been linked to stroke, head trauma, and a history of psychiatric disease.

Foreign accent syndrome, also known as dysprosody, is a rare speech disorder that can result in a person’s speech pattern changing to mimic a foreign accent. While the syndrome can be caused by various medical conditions, it remains a poorly understood phenomenon.