This book offers a radical re-examination of the history of the Cornish language, challenging the long-held belief that it became extinct with the death of Dolly Pentreath in 1777. Instead, it reveals compelling evidence that Cornish continued to be used throughout the 19th century, by the working class, by academics, and by those seeking to preserve the language. Exploring the research of antiquarians such as Dr. Fred W.P. Jago, Reverend Lach-Szyrma, and Henry Jenner, this book uncovers overlooked accounts of Cornish speakers and reassesses their linguistic knowledge. By tracing the language’s survival beyond its supposed extinction, the author argues that during the nineteenth century Cornish should be classified as critically endangered rather than extinct. Essential for scholars of minority languages, heritage researchers, and the Cornish language community, this book reshapes our understanding of Cornish history—proving that its story is one of resilience, not disappearance.