Cornish (Kernewek or Kernowek) is a Brythonic Celtic language and a recognised minority language of the United Kingdom, spoken in Cornwall. The language continued to function as a community language in parts of Cornwall until the late 18th century, and a process to revive the language was started in the early 20th century, continuing to this day.

The revival of Cornish began in 1904 when Henry Jenner, a Celtic language enthusiast, published his book Handbook of the Cornish Language. In his work he observed, "There has never been a time when there has been no person in Cornwall without a knowledge of the Cornish language." Jenner's work was based on Cornish as it was spoken in the 18th century, although his pupil Robert Morton Nance later steered the revival to the style of the 16th century, before the language became more heavily influenced by English. This set the tone for the next few decades; as the revival gained pace, learners of the language disagreed on which style of Cornish to use, and a number of competing orthographies were in use by the end of the century.