The Cornish language is usually divided into four phases – old, middle, late and revived. This device is now taken for granted and usually goes unquestioned. But is it the best way to understand the history of the language?

It’s a classification based on linguistics. The phases of Cornish are supposed to reflect changes in its spelling, its syntax (sentence structure) and its lexicon (vocabulary). Changes in spelling there certainly were, with the written conventions used by Cornish scribes fading away (or forgotten) after the Reformation of the first half of the 1500s. They were replaced by more idiosyncratic and individual spellings, either based on the English of the time or, after 1700, on the spelling system invented by the Celtic scholar Edward Lhuyd.

However, the spelling shift may well mask some underlying continuities. For example, the Cornish phrases written down by the Englishman Andrew Borde, on a visit to Cornwall in the 1530s, look very similar to the Cornish of the native writers of the later 1600s. They’re also very unlike the Cornish of the religious literature being copied and written in the sixteenth century. It’s more than possible that spoken Cornish changed a lot less in the century or century and a half after the 1530s than is implied by the change in written Cornish. For instance, how can we be sure that the word for wood – coys as written in the sixteenth century (the letter y denoting a long vowel) was pronounced that differently from the seventeenth century coose, where the mute e and the double o stand in for the y? In similar fashion the conservatism of the Cornish scribal tradition and the constraints posed by the dramatic form of the surviving literature may have masked earlier changes between the 1300s and the early 1500s.

Given these uncertainties, changes in placename spellings, surname distributions and documentary evidence might provide a safer way of understanding the historical geography of Cornish. This gives us similar periods but a different rationale for them, as follows.

The brief account of the history of the language here is based on an analysis of the list of historic placenames collected in the mid-20th century by J.E.B.Gover. We’re told that this list has inaccuracies and is incomplete, but so far Cornish placename specialists have failed to publish a more accurate and comprehensive list. In its absence Gover’s valuable work has to remain the main source for conclusions about the broad contours of change.