Cornish
Cornish (Kernewek) is a Southwestern Brittonic language of the Celtic family, descended from the Common Brittonic once spoken across the island of Britain. Its closest living relatives are Welsh and Breton, with which it shares a common ancestor; the three diverged as the Brittonic-speaking peoples of the west and southwest were separated from one another by the expansion of Old English. For roughly a millennium Cornish was the everyday speech of Cornwall, the long peninsula that forms the southwestern tip of England.
The language retreated westward over centuries under sustained pressure from English, which advanced as the language of administration, commerce, and religion. The Reformation proved decisive: the imposition of an English-language liturgy after 1549 denied Cornish the prestige and standardisation that a vernacular Bible and Prayer Book gave to Welsh. By the eighteenth century, fluent Cornish survived only in a handful of fishing communities at the far west of the peninsula.
Tradition assigns the role of “last native speaker” to Dolly Pentreath of Mousehole, who died in 1777. The claim is a simplification — semi-speakers and people retaining fragments of the language persisted well into the nineteenth century, John Davey of Zennor (d. 1891) among the most often cited — but the broad outline holds: as a community language transmitted from parent to child, traditional Cornish fell silent in the late 1700s.
What distinguishes Cornish from most entries in this file is what came afterward. Beginning with Henry Jenner’s Handbook of the Cornish Language in 1904, a deliberate revival reconstructed and re-taught the language from its written record. Cornish today has several hundred speakers, a standardised orthography, and children learning it; it is recognised under the European Charter for Regional or Minority Languages. It is, in the precise sense, a revived language.