For those unfamiliar with Cornish, it is classed as a p-Celtic member of the family of Celtic languages, which was once spoken across much of Europe, and is now restricted to the insular world and Brittany: only Cornish, Welsh and Breton (all p-Celtic), and Manx, Scots Gaelic and Irish (all q-Celtic) still extant. p-Celtic words such as peduar [W] (four) have q-Celtic equivalents cethar [Ir] (Russell, 1995, p.14)
The etymology, morphology, syntax and phonology of Cornish and the other Celtic languages ultimately derive from a putative proto-Indo European or proto-Celtic language or family of languages spoken in Britain in pre-history (ibid, p.2). In order to make sense of what Late South-western British (Primitive Cornish) and Old Cornish names were like and then reconstruct them, Cornish needs to be placed within the Celtic family tree and similarities with its relatives identified.
Over the decades several models of language evolution have been proposed and studies are in progress to determine the etymology of early Celtic names, particularly those of Gaulish and Hispano-Celtic origin. There has been significant recent work relating to the provenance of possible Continental Celtic languages and peoples, and in particular identifying differences in syntax and phonology. This has included studies in Lepontic, (246 hits on Academia.edu [AE]) Tartesian (74 results), and Gallaecian (62 mentions). Most pertinently are recent studies in proto-Brittonic (15 AE papers), which has a direct bearing on Cornish, and demonstrating that morphological reconstruction for Late South-western British is most definitely worthwhile.
Not withstanding that proto-Celtic and proto-Brittonic are reconstructions or models (and thus ultimately unverifiable) they may still be used to inform the morphology and phonology of Late South-western British and Old Cornish, and constrain morphological reconstructions to their most probable forms, an essential pre-requisite when analysing archaic anthroponyms.
For any reconstruction of Late South-western British names to be acceptable, it is reasonable to ask whether it was truly the primary language of the peninsula for a sustained period, without interference from other languages and therefore relevant to place name study. The accepted method of reconstruction is called comparative historical linguistics. This requires comparison of a language against its siblings and looking for both similarities and differences, which also enables normalisation of those names into a form suitable for subsequent geo-spatial processing, a comprehensive description of which is provided in staple textbooks such as Campbell (2004).
The majority of archaic names are from monumental inscriptions, but they do not provide enough material to reconstruct an entire language. Until recently the job of ‘joining the dots’ between these forms and modern Celtic languages, and then producing a full description of their morphology, phonology and grammar has been the preserve of philologists. C19 and C20 philologists have laid the foundations for modern linguists, so a review of their work is essential, but before reviewing philology, manuscript transcription and translation, a digression is necessary to establish the credentials of Cornwall, the Cornish language and continuous settlement by the people called the Cornish. (See Part 2!!)