The Celtic language family is a sub group of the Indo-European language family. Before the Roman Empire, Celtic Languages were spoken throughout Europe from Turkey to Spain. In modern times, they are primarily spoken in the British Isles, Ireland and Brittany, France.
There are two major ways of classifying the languages within the family: One is based on geographic distribution, the other based on an important sound change in the way Proto-Indo-European *kw has been realized.
The latter organization splits languages by whether they have kept PIE *kw as /p/ or /k/. Languages that use the /k/ pronunciation are known as Q-Celtic languages. For example the PIE word for 4 has been reconstructed as *kwétuōr. In the Q-celtic languages, the cognates of the kw retains the velar quality and show up as a /k/ sound (orthographically represented in all the languages as either <c> or <k>): Irish: ceathair, Scottish Gaelic: ceithir, Manx: kiare. In the P-Celtic languages the velar quality of the sound is lost, but the labial articulation of the w is retained, resulting in a /p/ sound: Welsh: pedwar, Cornish: peswar/peder, Breton: pevar/peder. It is thought that the extinct languages spoken on most of the continent were P-Celtic, but Celtiberian, spoken in what is now Spain and Portugal, was Q-Celtic.
A different organization of the languages is based on their geographic location. This divides the family into Continental Celtic, which were spoken on the European continent. This includes Gaulish, Lepontic, Galatian, Noric, CeltiIberian, Gallaecian, all of which are now extinct. The other group are known as the Insular Celtic languages and represent the languages spoken in the British Isles and Ireland. These include the Modern languages of Irish, Scottish Gaelic, Manx, Welsh, Cornish and Breton. Although Breton is now spoken on the continent in France, it is an Insular language because it was brought to Brittany (a.k.a Armorica), relatively late by immigrants from Cornwall and Devon in England. It is not directly related to Gaulish, although there may have been language contact between the two. The insular languages have in common VSO word order, initial consonant mutations, and inflected prepositions.
Within the insular subgroup, there is a further division into Brythonic (or Brittonic) and Goidelic. The modern Brythonic languages are Welsh, Cornish and Breton, all of which are P-Celtic. The modern Goidelic languages are Irish, Scottish Gaelic and Manx, all of which are Q-Celtic. The Brythonic languages are all genetically related to the language spoken by the ancient Britains: Brittonic, which may have had many different forms including Old Welsh, Cumbric and Pictish. All of the Goidelic languages are descended from Old Irish.
- https://en.wikipedia.org/wiki/Celtic_languages(link is external)
- https://en.wikipedia.org/wiki/Continental_Celtic_languages(link is external)
- https://en.wikipedia.org/wiki/Insular_Celtic_languages(link is external)
- https://en.wikipedia.org/wiki/Goidelic_languages(link is external)
- https://en.wikipedia.org/wiki/Brittonic_languages(link is external)
- Russell, Paul (1995). An Introduction to the Celtic Languages. Longman. ISBN(link is external) 0582100828(link is external)
- Ball, Martin J. & James Fife (ed.) (1993). The Celtic Languages. London: Routledge. ISBN(link is external) 0-415-01035-7(link is external).