Welcome to Kernewek Dew. It is important that, if you have not already, go through Kernewek Onan as what is taught there is built upon here
Chons da!
Good Luck!
Istori An Taves Kernewek/History of the Cornish Language
Cornish is a member of the Brythonic Branch of Celtic, along with Welsh and Breton, but also, less known, Devonian and Cumbric. The Other Branch of the Celtic Language is Goidelic, with Scottish Gaelic, Irish and Manx.
British was spoken in the pre-Roman period, and has borrowed extensively from Latin (for example the word "scrifa" "write" is from Latin SCRIBO, also "kegyn" from COQUINA). In its Cornish form, it was spoken until 1800. Breton and Welsh, the other daughters of British survived to this day.
From the later maedieval period Cornish was pushed back West, the last native Cornish speaker, according to legend, is Dolly Pentreath of St. Columb Major in 1777, whose last words were "meea na vidna cowza sowznack" OR in the standard form "my na mynnes kewsel Sowsnek" and means "I don't want to speak English" or "I will not speak English". But there are some contemporary reports that people carried on using Cornish well into the 19th century.
By the 1900's, no one spoke Cornish. But, a man called Henry Jenner, who heard of the Cornish Language as a young boy, researched it all his life, he revived the Cornish Language and started the first Gorsedh Kernow.
Now, an estimated 3000 people know some Cornish, with 300-500 able to speak it fluently.