Alun Jones of Bath said he did learn to speak Welsh as a child because he spent four years during World War II living in Wales, The Independent reported Thursday. His relatives there were Welsh speakers.
But he had forgotten most of his Welsh until the stroke.
"It gave my wife the shock of her life when I started speaking Welsh," he told the newspaper in Welsh. "After the stroke it was hard going. I've managed to remember English but I've almost forgotten Welsh again."
Strokes often leave victims unable to speak or struggling to recall words they once knew, a condition known as aphasia. But experts say a few victims uncover hidden abilities.
"We believe the damaged brain finds new pathways, which unlock memories or knowledge that is latent but not expressed," Joe Korner of the Stroke Association said.