Although it appears to have been named after the Cornouii (whose territory, in historical times, was actually centered on far-away Wroxeter), at the time of the Roman occupation Cornwall (and the rest of the southwestern British peninsula) was under the rule of the Dumnonii. Migration from the Dumnonian territory to Armorica on the Continent played a major role in the formation of Brittany as a linguistic and cultural entity. The collapse of Roman rule in Britain and the increasing encroachment of the English, beginning in the mid-5th century, eventually led to the Dumnonian territory being separated from the rest of Britain when the English reached the mouth of the Severn in 577. The English continued to attack the lands of the "West-Welsh" (as they called the Dumnonii), eventually placing the border between English and British-Celtic realms at the river Tamar in 936, thus creating the historical entity of Cornwall. Cornish autonomy under English suzerainty continued to be respected for a number of centuries, although little by little the region was merged administratively with England.

  Despite this, the linguistic and cultural uniqueness of Cornwall remained evident throughout the Middle Ages. The earliest records of the language (glosses in Latin manuscripts, mostly from the 10th century) suggest that there was little difference in speech at first between the various Brythonic-speaking areas in Britain and Armorica. As the Middle Ages progressed, however, increasing discrepancies appeared between the speech of Wales on the one hand and that of Cornwall and Brittany on the other. Our most extensive document on Old Cornish (Kernewek Koth) is the "Cottonian Vocabulary" or _Vocabularium cornicum_, a 12th-century Cornish-Latin glossary. Many of the stories that became part of the Arthurian mythos (like that of Tristan and Isold) certainly originated in Cornwall and may have been given written form in Kernewek, but unfortunately no such manuscripts have survived.

As there continued to be frequent contacts between the Celts on both sides of the Channel, a certain cultural cohesion was maintained between Cornwall and Brittany, so that Kernewek and Brezhoneg remained mutually intelligible to a large degree until the end of the Middle Ages. This allowed Cornish visitors to participate in the great religious festivals of Brittany, and to enjoy the vernacular religious theatre that was a conspicuous feature of such events. During the 1400's and early 1500's miracle-plays of a similar nature were composed in Kernewek for performance during the liturgical year. The language of these plays is Middle Cornish (Kernewek Kres). They are rich in vocabulary and idiom and, taken together, form the bulk of the Cornish literary heritage (one of them, _Bywnans Ke_, was discovered as late as 2002!).

With the coming of the Protestant Reformation (which the Cornish at first strongly resisted), major changes were imposed on Cornish society, with grave consequences for native Cornish language and culture. Contacts with Catholic Brittany were curtailed, putting an end to the cultural reinforcement that had come from that quarter. English became the sole language of the social and intellectual elite (even so, English didn't seriously replace Kernewek as a community language until the later 1600's; in the late 1500's John Tregear thought it profitable to translate many of Bishop Bonner's sermons into Kernewek, so that ordinary Cornish congregations could understand them). By the 1700's the language was spoken only in the area of Penzance, where antiquarians like Nicholas Boson, William Gwavas, and others busily collected whatever they could glean from the last two generations of native speakers. This stage of the language is called Late Cornish (Kernewek Diwedhes). It is characterized by a breakdown of the old verbal inflection system and a syntax strongly influenced by English; the orthography used to write it down also owes a great deal to English phonetic spelling.

Most books state that the last native speaker of Cornish was Dolly Pentreath, who died in 1777. In fact, contemporary sources make it clear that there were other Cornish-speakers around at the time: for example, William Bodener, a fluent speaker from Mousehole, lived on until 1794. Today the consensus is that the last person to have some traditional knowledge of Kernewek was John Davey, who died in 1891.  

Even so, the language refused to stay dead. The Cornish scholar William Jenner at first approached its study as an antiquarian subject, but then developed a personal bond with it, taught himself to speak it, and by 1900 was encouraging others to use it as an everyday language, expressive of Cornish ethnic identity. His efforts gained the attention and respect of the international pan-Celtic movement, and found support at home.

For the first few decades the Cornish revival suffered from a lack of clear standards as far as spelling and grammar were concerned. But at the end of the 1920's Robert Morton Nance (one of Jenner's collaborators) proposed a new standard which he called Unified Cornish (Kernewek Unys), taking Middle Cornish (from the period when Kernewek last was a self-sufficient community language) as the basis for grammar and syntax, but adopting vocabulary and tips on pronunciation from all available sources. This proved very effective, and was the form of the language several generations of Cornish-learners came to acquire.

Serviceable as it was, however, Unified Cornish was far from perfect: in particular, its orthography failed to represent the native vowel system accurately. In the 1980's separate attempts at improving the situation led to the emergence of several competing standards: Ken George's Kernewek Kemmyn proposed a phonemic spelling system (one written symbol per phoneme); Richard Gendall, on the contrary, created a standard rigidly based on Late Cornish alone; Nicholas Williams' Revised Unified Cornish was a less radical modification of Nance's standard; and many people, of course, remained faithful to the Unified Cornish they had learned.  At first this diversity of standards led to intensely hostile factionalism, which did great harm to the revival movement as a whole. Today, fortunately, passions have cooled and there is more tolerance for the diversity.

 Many thousands of people have passed proficiency exams in Kernewek and have a working knowledge of it, but only a few hundred speak it fluently as an everyday language. Nevertheless, as Cornish-learners have passed the language on to their children (and encouraged them to use it among themselves through special play-groups like Dalleth) a generation of new native speakers is now nearing adulthood. In 2002 Kernewek was officially recognised by the UK government as a "Lesser-Used Language" under the EC charter, an event which will no doubt enhance the language's standing and appeal.

All the currently used standards of Kernewek are equally valid entry-points into the study of the language. For the purposes of this course, however, we strongly recommend that you begin with Kernewek Kemmyn – because it's the easiest to learn, is probably the most widespread at this time (having been adopted by both the Cornish Language Society and the Cornish Language Board), and is the medium of some particularly useful resources, like the monthly all-Cornish magazine _An Gannas_, which features organisational news, poetry, fiction, language scholarship, commentary on local and international politics, etc.