The Nuclear Celtic languages separated from Hispano-Celtic around 900 BC, possibly due toPhoenician influence causing Hispano-Celtic to drift away from a common Celtic cultural sphere.[3]
The terms used to refer to the Celtic grouping comprisingGaulish,Goidelic andBrittonic, and also the position ofLepontic in this grouping, vary by author.
Eska definesNuclear Celtic as includingGaulish,Lepontic, and theInsular Celtic languages (Goidelic andBrittonic), and furthermore definesCore Celtic as a sub-branch of Nuclear Celtic that excludesLepontic.[1] On the other hand, Stifter redefinesCore Celtic to include Lepontic,[5] making it synonymous to what Eska termsNuclear Celtic.
Eska's internal taxonomy of Nuclear Celtic is as follows:
Schrijver definesNorth Celtic as referring to what Eska callsCore Celtic, namely a grouping ofGaulish andInsular Celtic to the exclusion ofLepontic. He also groupsHispano-Celtic andLepontic together in a contrasting grouping he callsSouth Celtic.[6] Schrijver's Celtic taxonomy is as follows:[7]
However, Jørgensen, despite borrowing Schrijver'sNorth Celtic andSouth Celtic terminology, redefinesNorth Celtic to include Lepontic as well.[4] This redefined North Celtic is thus identical to Eska's Nuclear Celtic. Jørgensen's redefinition of North Celtic is as follows:
Gallo-Insular Celtic andGallo-Brythonic–Goidelic are terms coined, respectively, by Kim McCone (who supports anInsular Celtic clade) andJohn T. Koch (who follows aGallo-Brythonic hypothesis). Gallo-Insular Celtic's family tree is defined by McCone as follows:[2]
Common characteristics of the Nuclear Celtic branch (and the Core Celtic sub-branch as defined by Eska) include:
*st becoming a phoneme known astau gallicum, which was notated variously in Gaulish but merged with-ss- in Goidelic. In contrast, Hispano-Celtic preserved*st as is.[1]
Complete monophthongization of the diphthong*ei to/eː/ in non-final position.[1]
Refashioning of the (preserved in Hispano-Celtic) inflected relative pronoun*yos (feminine*yā) into an uninflected relative particle*yo.[2]
Spread of the o-stem genitive singular*-ī, completely absent in Hispano-Celtic.[1]
A genitive plural*-om, contrasting with its Hispano-Celtic counterpart-um. Eska believes that*-om is a shared innovation of Nuclear Celtic with Hispano-Celtic preserving an older ending.[8] However, Prósper believes the reverse was the case, with Hispano-Celtic innovating-um (and even there,-om was retained in some dialects);-om elsewhere would be a retention.[9]
The repurposing of*to, originally a connecting particle, into a preverb*to-; such a preverb appears in Cisalpine Gaulish and Insular Celtic.[10]
The rise of a characteristic verb complex, including the ability to affix multiple preverbs to a verb simultaneously; both Gaulish and early Insular Celtic allow double prefixation of verbs.[11]
Eska, Joseph (2017). "The dialectology of Celtic". In Jared Klein; Brian Joseph; Matthias Fritz (eds.).Handbook of Comparative and Historical Indo-European Linguistics. Berlin: De Gruyter Mouton. pp. 1264–1274.
Koch, John T. (2020).Celto-Germanic: Later Prehistory and Post-Proto-Indo-European vocabulary in the North and West. Aberystwyth: University of Wales Centre for Advanced Welsh and Celtic Studies.
McCone, Kim (2006).The Origins and Development of the Insular Celtic Verbal Complex. Maynooth studies in Celtic linguistics. Department of Old Irish, National University of Ireland.ISBN978-0-901519-46-7.
Prósper, Blanca María (2024). "The Inscriptions of Todi (Umbria) and Vergiate (Transpadana): A Study in Cisalpine Celtic Epigraphic Habits, Noun Morphology, and the Linguistic Classification of Lepontic". In David M. Goldstein; Stephanie W. Jamison; Anthony D. Yates (eds.).Proceedings of the 34th Annual UCLA Indo-European Conference: Los Angeles, October 27th and 28th, 2023. pp. 215–250.
Schrijver, Peter (2015). "Pruners and trainers of the Celtic family tree: The rise and development of Celtic in the light of language contact". In Liam Breatnach (ed.).Proceedings of the XIV International Congress of Celtic Studies. Dublin: Dublin Institute of Advanced Studies. pp. 191–219.
Stifter, David (2023). "With the Back to the Ocean: The Celtic Maritime Vocabulary". In Kristian Kristiansen; Guus Kroonen; Eske Willerslev (eds.).The Indo-European Puzzle Revisited Integrating Archaeology, Genetics, and Linguistics. Cambridge University Press.
