Foreign accent syndrome makes a person sound as if they suddenly speak their native language with a foreign accent, but patients never gain a new accent or a new language. The episode explains it as a breakdown in articulatory planning: vowels shift, diphthongs flatten into single sounds, and English speakers drift from stress timed rhythm toward the syllable timed rhythm of French or Spanish. Professor Nick Miller describes the accent as being in the ear of the listener, not the mouth of the speaker. Stroke is the leading cause, with damage usually in the left hemisphere’s premotor cortex, motor cortex, basal ganglia, or Broca’s area.

French neurologist Pierre Marie reported the first case in 1907, and only 62 cases were recorded worldwide between 1941 and 2009. In 1941 a Norwegian woman known as Astrid L. was struck by shrapnel in an air raid and afterward sounded German to her neighbors, who shunned her during the occupation. Later cases include Sarah Colwill of Devon after a migraine, Lisa Alamia of Texas after jaw surgery in 2016, and George Michael after a three week coma in 2012. Linguists Jo Verhoeven and Peter Mariën described four subtypes in 2010.

• In a pool of 112 patients, 97 percent were adults, 67 percent were female, and only 12.5 percent had prior exposure to the accent
• The mixed subtype describes patients who lean into the new accent as a protective new persona
• Electropalatography uses an electrode studded artificial palate to show where the tongue touches
• Only about 25 percent of patients reach full remission
• Electromagnetic articulography builds a live 3D image of the patient’s tongue for visual feedback