|Formerly widespread in Europe; today British Isles, Brittany, Patagonia and Nova Scotia|
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The Celtic languages (usually pronounced // but sometimes //) are descended from Proto-Celtic, or "Common Celtic"; a branch of the greater Indo-European language family. The term "Celtic" was first used to describe this language group by Edward Lhuyd in 1707.
Modern Celtic languages are mostly spoken on the north-western edge of Europe, notably in Ireland, Scotland, Wales, Brittany, Cornwall, and the Isle of Man, and can be found spoken on Cape Breton Island. There are also a substantial number of Welsh speakers in the Patagonia area of Argentina. Some people speak Celtic languages in the other Celtic diaspora areas of the United States, Canada, Australia, and New Zealand. In all these areas, the Celtic languages are now only spoken by minorities though there are continuing efforts at revitalization. Welsh is the only Celtic language not classified as "endangered" by UNESCO.
During the 1st millennium BC, they were spoken across much of Europe, in the Iberian Peninsula, from the Atlantic and North Sea coastlines, up to the Rhine valley and down the Danube valley to the Black Sea, the northern Balkan Peninsula and in central Asia Minor. The spread to Cape Breton and Patagonia occurred in modern times. Celtic languages, particularly Irish, were spoken in Australia before federation in 1901 and are still used there to some extent.
SIL Ethnologue lists six "living" Celtic languages, of which four have retained a substantial number of native speakers. These are the Gaelic languages (i.e. the Irish language and Scottish Gaelic - both descended from Old Irish), and the Brittonic languages (i.e. Welsh and the Breton language - both descended from Old Brittonic).
The other two, Cornish and Manx, were spoken into modern times but later died as spoken community languages. For both these languages, however, revitalization movements have led to the adoption of these languages by adults and children and produced some native speakers.
|Language||Native name||Grouping||Number of native speakers||Number of people who have one or more skills in the language||Main area(s) in which the language is spoken||Regulated by/language body|
|Welsh||Cymraeg||Brythonic||431,000 (14.6% of the population of Wales) considers themselves to be fluent in Welsh (2011)||Around 721,700 (2011) total speakers
— Wales: 562,000 speakers, 19.0% of the population of Wales,
— England: 150,000
— Chubut Province, Argentina: 5,000
— United States: 2,500
— Canada: 2,200
Y Wladfa, Chubut
|— Welsh Language Commissioner (Meri Huws)
— The Welsh Government
(previously the Welsh Language Board Bwrdd yr Iaith Gymraeg)
In the Republic of Ireland, 94,000 people use Irish daily outside the education system.
Republic of Ireland:
|Ireland||Foras na Gaeilge|
|Breton||Brezhoneg||Brythonic||206,000||356,000||Brittany||Ofis Publik ar Brezhoneg|
|Scottish Gaelic||Gàidhlig||Goidelic||57,375 (2011) in Scotland as well as 1,275 (2011) in Nova Scotia||87,056 (2011) in Scotland||Scotland||Bòrd na Gàidhlig|
|Cornish||Kernewek||Brythonic||600||3,000||Cornwall||Keskowethyans an Taves Kernewek|
|Manx||Gaelg||Goidelic||100+, including a small number of children who are new native speakers||1,823||Isle of Man||Coonceil ny Gaelgey|
- Shelta, based largely on Irish with influence from an undocumented source (some 86,000 speakers in 2009).
- Some forms of Welsh-Romani or Kååle also combined Romany itself with Welsh language and English language forms (extinct).
- Beurla-reagaird, Highland travellers language
Proto-Celtic divided into various branches:
- Lepontic, the oldest attested Celtic language (from the 6th century BC).
- Celtiberian, anciently spoken in the Iberian peninsula, in parts of modern Aragón, Old Castile, and New Castile in Spain. The relationship of Celtiberian with Gallaecian, in the northwest of the peninsula, is uncertain.
- Gaulish languages, including Galatian and possibly Noric. These languages were once spoken in a wide arc from Belgium to Turkey. They are now all extinct.
- Brittonic, including the living languages Breton, Cornish, and Welsh, and the extinct languages Cumbric and Pictish though Pictish may be a sister language rather than a daughter of Common Brittonic. Before the arrival of Scotti on the Isle of Man in the 9th century, there may have been a Brittonic language in the Isle of Man.
- Goidelic, including the living languages Irish, Manx, and Scottish Gaelic.
Scholarly handling of the Celtic languages has been rather argumentative owing to scarceness of primary source data. Some scholars (such as Cowgill 1975; McCone 1991, 1992; and Schrijver 1995) distinguish Continental Celtic and Insular Celtic, arguing that the differences between the Goidelic and Brittonic languages arose after these split off from the Continental Celtic languages. Other scholars (such as Schmidt 1988) distinguish between P-Celtic and Q-Celtic, putting most of the Gaulish and Brittonic languages in the former group and the Goidelic and Celtiberian languages in the latter. The P-Celtic languages (also called Gallo-Brittonic) are sometimes seen (for example by Koch 1992) as a central innovating area as opposed to the more conservative peripheral Q-Celtic languages.
The Breton language is Brittonic, not Gaulish, though there may be some input from the latter, having been introduced from Southwestern regions of Britain in the post-Roman era and having evolved into Breton – still partially intelligible by modern Welsh and Cornish speakers.
In the P/Q classification schema, the first language to split off from Proto-Celtic was Gaelic. It has characteristics that some scholars see as archaic, but others see as also being in the Brittonic languages (see Schmidt). In the Insular/Continental classification schema, the split of the former into Gaelic and Brittonic is seen as being late.
The distinction of Celtic into these four sub-families most likely occurred about 900 BC according to Gray and Atkinson but, because of estimation uncertainty, it could be any time between 1200 and 800 BC. However, they only considered Gaelic and Brythonic. The controversial paper by Forster and Toth included Gaulish and put the break-up much earlier at 3200 BC ± 1500 years. They support the Insular Celtic hypothesis. The early Celts were commonly associated with the archaeological Urnfield culture, the Hallstatt culture, and the La Tène culture, though the earlier assumption of association between language and culture is now considered to be less strong.
There are legitimate scholarly arguments in favour of both the Insular Celtic hypothesis and the P-Celtic/Q-Celtic hypothesis. Proponents of each schema dispute the accuracy and usefulness of the other's categories. However, since the 1970s the division into Insular and Continental Celtic has become the more widely held view (Cowgill 1975; McCone 1991, 1992; Schrijver 1995), but in the middle of the 1980s, the P-Celtic/Q-Celtic hypothesis found new supporters (Lambert 1994), because of the inscription on the Larzac piece of lead (1983), the analysis of which reveals another common phonetical innovation -nm- > -nu (Gaelic ainm / Gaulish anuana, Old Welsh enuein "names"), that is less accidental than only one. The discovery of a third common innovation, would allow the specialists to come to the conclusion of a Gallo-Brittonic dialect (Schmidt 1986; Fleuriot 1986).
The interpretation of this and further evidence is still quite contested, and the main argument in favour of Insular Celtic is connected with the development of the verbal morphology and the syntax in Irish and British Celtic, which Schumacher regards as convincing, while he considers the P-Celtic/Q-Celtic division unimportant and treats Gallo-Brittonic as an outdated hypothesis. Stifter affirms that the Gallo-Brittonic view is "out of favour" in the scholarly community as of 2008 and the Insular Celtic hypothesis "widely accepted".
When referring only to the modern Celtic languages, since no Continental Celtic language has living descendants, "Q-Celtic" is equivalent to "Goidelic" and "P-Celtic" is equivalent to "Brittonic".
Within the Indo-European family, the Celtic languages have sometimes been placed with the Italic languages in a common Italo-Celtic subfamily, a hypothesis that is now largely discarded, in favour of the assumption of language contact between pre-Celtic and pre-Italic communities.
How the family tree of the Celtic languages is ordered depends on which hypothesis is used:
Insular Celtic hypothesis
Eska (2010) evaluates the evidence as supporting the following tree, based on shared innovations, though it is not always clear that the innovations are not areal features. It seems likely that Celtiberian split off before Cisalpine Celtic, but the evidence for this is not robust. On the other hand, the unity of Gaulish, Goidelic, and Brittonic is reasonably secure. Schumacher (2004, p. 86) had already cautiously considered this grouping to be likely genetic, based, among others, on the shared reformation of the sentence-initial, fully inflecting relative pronoun *i̯os, *i̯ā, *i̯od into an uninflected enclitic particle. Eska sees Cisalpine Gaulish as more akin to Lepontic than to Transalpine Gaulish.
Eska considers a division of Transalpine–Goidelic–Brittonic into Transalpine and Insular Celtic to be most probable because of the greater number of innovations in Insular Celtic than in P-Celtic, and because the Insular Celtic languages were probably not in great enough contact for those innovations to spread as part of a sprachbund. However, if they have another explanation (such as an SOV substratum language), then it is possible that P-Celtic is a valid clade, and the top branching would be:
- Transalpine–Goidelic–Brittonic (P-Celtic hypothesis)
Characteristics of Celtic languages
||This section may be too technical for most readers to understand. (March 2008)|
Although there are many differences between the individual Celtic languages, they do show many family resemblances. While none of these characteristics are necessarily unique to the Celtic languages, there are few if any other languages which possess them all. They include:
- consonant mutations (Insular Celtic only)
- inflected prepositions (Insular Celtic only)
- two grammatical genders (modern Insular Celtic only; Old Irish and the Continental languages had three genders)
- a vigesimal number system (counting by twenties)
- e.g. Cornish hwetek ha dew ugens "fifty-six" (literally "sixteen and two twenty")
- verb–subject–object (VSO) word order (probably Insular Celtic only)
- an interplay between the subjunctive, future, imperfect, and habitual, to the point that some tenses and moods have ousted others
- an impersonal or autonomous verb form serving as a passive or intransitive
- Welsh dysgaf "I teach" vs. dysgir "is taught, one teaches", Irish "déanaim" "I do/make" vs. "déantar" "is done"
- no infinitives, replaced by a quasi-nominal verb form called the verbal noun or verbnoun
- frequent use of vowel mutation as a morphological device, e.g. formation of plurals, verbal stems, etc.
- use of preverbal particles to signal either subordination or illocutionary force of the following clause
- infixed pronouns positioned between particles and verbs
- lack of simple verb for the imperfective "have" process, with possession conveyed by a composite structure, usually BE + preposition
- Cornish yma kath dhymm "I have a cat", literally "there is a cat to me"
- use of periphrastic phrases to express verbal tense, voice, or aspectual distinctions
- distinction by function of the two versions of BE verbs traditionally labelled substantive (or existential) and copula
- bifurcated demonstrative structure
- suffixed pronominal supplements, called confirming or supplementary pronouns
- use of singulars and/or special forms of counted nouns, and use of a singulative suffix to make singular forms from plurals, where older singulars have disappeared
(Irish) Ná bac le mac an bhacaigh is ní bhacfaidh mac an bhacaigh leat.
(Literal translation) Don't bother with son the beggar's and not will-bother son the beggar's with-you.
- bhacaigh is the genitive of bacach. The igh the result of affection; the bh is the lenited form of b.
- leat is the second person singular inflected form of the preposition le.
- The order is verb–subject–object (VSO) in the second half. Compare this to English or French (and possibly Continental Celtic) which are normally subject–verb–object in word order.
(Welsh) pedwar ar bymtheg a phedwar ugain
(literally) four on fifteen and four twenties
- bymtheg is a mutated form of pymtheg, which is pump ("five") plus deg ("ten"). Likewise, phedwar is a mutated form of pedwar.
- The multiples of ten are deg, ugain, deg ar hugain, deugain, hanner cant, trigain, deg a thrigain, pedwar ugain, deg a phedwar ugain, cant.*
|aber||aber||aber||inbhear||inbhir||inver||estuary, mouth of a river|
|gwefus||gweus||gweuz||liopa, beol||bile, lip||meill||lip (anatomical)|
|arian||mona, arghans||moneiz, arcʼhant||airgead||airgead||argid||silver, money|
|tu fas, tu allan||yn-mes||er-maez||amuigh||a-muigh||mooie||outside|
|ysmygu||megi||mogediñ, butuniñ||tobac a chaitheamh||smocadh||toghtaney/smookal||(to) smoke|
Article 1 of the Universal Declaration of Human Rights:
All human beings are born free and equal in dignity and rights. They are endowed with reason and conscience and should act towards one another in a spirit of brotherhood.
- Irish: Saolaítear na daoine uile saor agus comhionann ina ndínit agus ina gcearta. Tá bua an réasúin agus an choinsiasa acu agus dlíd iad féin d'iompar de mheon bráithreachas i leith a chéile.
- Manx: Ta dagh ooilley pheiagh ruggit seyr as corrym ayns ard-cheim as kiartyn. Ren Jee feoiltaghey resoon as cooinsheanse orroo as by chair daue ymmyrkey ry cheilley myr braaraghyn.
- Scottish Gaelic: Tha gach uile dhuine air a bhreth saor agus co-ionnan ann an urram 's ann an còirichean. Tha iad air am breth le reusan is le cogais agus mar sin bu chòir dhaibh a bhith beò nam measg fhein ann an spiorad bràthaireil.
- Breton: Dieub ha par en o dellezegezh hag o gwirioù eo ganet an holl dud. Poell ha skiant zo dezho ha dleout a reont bevañ an eil gant egile en ur spered a genvreudeuriezh.
- Cornish: Genys frank ha par yw oll tus an bys yn aga dynita hag yn aga gwiryow. Enduys yns gans reson ha kowses hag y tal dhedha omdhon an eyl orth y gila yn spyrys a vrederedh.
- Welsh: Genir pawb yn rhydd ac yn gydradd â'i gilydd mewn urddas a hawliau. Fe'u cynysgaeddir â rheswm a chydwybod, a dylai pawb ymddwyn y naill at y llall mewn ysbryd cymodlon.
Possible Celtic languages
Languages that have been suggested as possibly Celtic:
- Pictish was for a long time thought to be a pre-Celtic, non-Indo-European language of Scotland. It is now generally accepted as Celtic.
- Lusitanian was spoken in the area between the Douro and Tagus rivers in what is now Portugal and part of Spain. It is known only by five inscriptions, together with various place names. It is an Indo-European language and some scholars have proposed that it may be a para-Celtic language that evolved alongside Celtic and is in a dialectic continuum with Tartessian and Gallaecian. This is tied to a theory of an Iberian origin for the Celtic languages. Other scholars see affinities with Italic and Old European.
- Tartessian, spoken in the south-west of the Iberia Peninsula. Tartessian is known by 95 inscriptions with the longest having 82 readable signs. It is not known to be Indo-European and is generally left unclassified. However, John T. Koch argues that Tartessian was a Celtic language.
- Nordhoff, Sebastian; Hammarström, Harald; Forkel, Robert; Haspelmath, Martin, eds. (2013). "Celtic". Glottolog 2.2. Leipzig: Max Planck Institute for Evolutionary Anthropology.
- "American Heritage Dictionary. Celtic: kel-tik, sel". Dictionary.reference.com. Retrieved 19 August 2011.
- The Celtic languages:an overview, Donald MacAulay, The Celtic Languages, ed. Donald MacAulay, (Cambridge University Press, 1992), 3.
- Cunliffe, Barry W. 2003. The Celts: a very short introduction. pg.48
- "Language by State – Scottish Gaelic" on Modern Language Association website. Retrieved 27 December 2007
- "Languages Spoken At Home" from Australian Government Office of Multicultural Interests website. Retrieved 27 December 2007
- Languages Spoken:Total Responses from Statistics New Zealand website. Retrieved 5 August 2008
- G. Leitner, Australia's Many Voices: Australian English--The National Language, 2004, pg. 74
- Koch, John T. (2006). Celtic Culture: A Historical Encyclopedia. ABC-CLIO. pp. 34, 365–366, 529, 973, 1053. Retrieved 15 June 2010.
- "A brief history of the Cornish language". Maga Kernow.
- Beresford Ellis, Peter (1990, 1998, 2005). The Story of the Cornish Language. Tor Mark Press. pp. 20–22. ISBN 0-85025-371-3.
- Staff. "Fockle ny ghaa: schoolchildren take charge". Iomtoday.co.im. Retrieved 19 August 2011.
- "'South West:TeachingEnglish:British Council:BBC". BBC/British Council website (BBC). 2010. Retrieved 9 February 2010.
- "Celtic Languages". Ethnologue. Retrieved 9 March 2010.
- Crystal, David (2010). The Cambridge Encyclopedia of Language. Cambridge University Press. ISBN 978-0-521-73650-3.
- Office for National Statistics 2011 http://ons.gov.uk/ons/rel/census/2011-census/key-statistics-for-unitary-authorities-in-wales/stb-2011-census-key-statistics-for-wales.html#tab---Proficiency-in-Welsh
- United Nations High Commissioner for Refugees. "World Directory of Minorities and Indigenous Peoples – UK: Welsh". UNHCR. Retrieved 23 May 2010.
- "Wales and Argentina". Wales.com website. Welsh Assembly Government. 2008. Retrieved 23 January 2012.
- "Table 1. Detailed Languages Spoken at Home and Ability to Speak English for the Population 5 Years and Over for the United States: 2006-2008 Release Date: April 2010" (xls). United States Census Bureau. 27 April 2010. Retrieved 2 January 2011.
- "2006 Census of Canada: Topic based tabulations: Various Languages Spoken (147), Age Groups (17A) and Sex (3) for the Population of Canada, Provinces, Territories, Census Metropolitan Areas and Census Agglomerations, 2006 Census - 20% Sample Data". Statistics Canada. 7 December 2010. Retrieved 3 January 2011.
- "Irish Examiner". Archives.tcm.ie. 24 November 2004. Retrieved 19 August 2011.
- Christina Bratt Paulston. Linguistic Minorities in Multilingual Settings: Implications for Language Policies. J. Benjamins Pub. Co. p. 81. ISBN 1-55619-347-5.
- Pierce, David (2000). Irish Writing in the Twentieth Century. Cork University Press. p. 1140. ISBN 1-85918-208-9.
- Ó hÉallaithe, Donncha (1999). Cuisle.
- www.cso.ie Central Statistics Office, Census 2011 - This is Ireland - see table 33a
- (French) Données clés sur breton, Ofis ar Brezhoneg
- 2011 Scotland Census, Table QS211SC.
- "National Household Survey Profile, Nova Scotia, 2011". Statistics Canada. 11 September 2013. Retrieved 7 June 2014.
- some 600 children brought up as bilingual native speakers (2003 estimate, SIL Ethnologue).
- Around 2,000 fluent speakers. "'South West:TeachingEnglish:British Council:BBC". BBC/British Council website (BBC). 2010. Retrieved 9 February 2010.
- "Anyone here speak Jersey?". Independent.co.uk. 11 April 2002. Retrieved 2011-08-19.
- "Documentation for ISO 639 identifier: glv". Sil.org. 14 January 2008. Retrieved 19 August 2011.
- "Isle of Man Census Report 2011" (PDF). Economic Affairs Division, Isle of Man Government Treasury. April 2012. p. 27. Retrieved 9 June 2014.
- "Shelta". Ethnologue. Retrieved 9 March 2010.
- "ROMLEX: Romani dialects". Romani.uni-graz.at. Retrieved 19 August 2011.
- Schumacher, Stefan; Schulze-Thulin, Britta; aan de Wiel, Caroline (2004). Die keltischen Primärverben. Ein vergleichendes, etymologisches und morphologisches Lexikon (in German). Innsbruck: Institut für Sprachen und Kulturen der Universität Innsbruck. pp. 84–87. ISBN 3-85124-692-6.
- "Ethnographic Map of Pre-Roman Iberia (circa 200 B.C.)". Arkeotavira.com. Retrieved 19 August 2011.
- Prósper, B.M. (2002). Lenguas y religiones prerromanas del occidente de la península ibérica. Ediciones Universidad de Salamanca. pp. 422–27. ISBN 84-7800-818-7.
- Villar F., B. M. Prósper. (2005). Vascos, Celtas e Indoeuropeos: genes y lenguas. Ediciones Universidad de Salamanca. pgs. 333–350. ISBN # 84-7800-530-7.
- Kenneth H. Jackson suggested that there were two Pictish languages, a pre-Indo-European one and a Pritenic Celtic one. This has been challenged by some scholars. See Katherine Forsyth's "Language in Pictland: the case against 'non-Indo-European Pictish'" PDF (27.8 MB). See also the introduction by James & Taylor to the "Index of Celtic and Other Elements in W. J. Watson's 'The History of the Celtic Place-names of Scotland'" PDF (172 KB[dead link]). Compare also the treatment of Pictish in Price's The Languages of Britain (1984) with his Languages in Britain & Ireland (2000).
- Barbour and Carmichael, Stephen and Cathie (2000). Language and nationalism in Europe. Oxford University Press. p. 56. ISBN 978-0-19-823671-9.
- Gray and Atkinson, RD; Atkinson, QD (2003). "Language-tree divergence times support the Anatolian theory of Indo-European origin". Nature 426 (6965): 435–439. Bibcode:2003Natur.426..435G. doi:10.1038/nature02029. PMID 14647380.
- Rexova, K.; Frynta, D and Zrzavy, J. (2003). "Cladistic analysis of languages: Indo-European classification based on lexicostatistical data". Cladistics 19 (2): 120–127. doi:10.1111/j.1096-0031.2003.tb00299.x.
- Forster, Peter; Toth, Alfred (2003). Toward a phylogenetic chronology of ancient Gaulish, Celtic, and Indo-European. The National Academy of Sciences.
- Renfrew, Colin (1987). Archaeology and Language: The Puzzle of Indo-European Origins. London: Jonathan Cape. ISBN 0224024957.
- James, Simon (1999). The Atlantic Celts: Ancient People or Modern Invention?. London: British Museum Press. ISBN 0714121657.
- Stifter, David (2008). Old Celtic Languages. p. 11.
- Joseph F. Eska (2010) "The emergence of the Celtic languages". In Martin J. Ball and Nicole Müller (eds.), The Celtic languages. Routledge.
- Wodtko, Dagmar S (2010). Celtic from the West Chapter 11: The Problem of Lusitanian. Oxbow Books, Oxford, UK. pp. 360–361. ISBN 978-1-84217-410-4.
- Cunliffe, Barry (2003). The Celts – A Very Short Introduction – see figure 7. Oxford University Press. pp. 51–52. ISBN 0-19-280418-9.
- Ballester, X. (2004). "Paramo' o del problema del la */p/ enceltoide". Studi Celtici 3: 45–56.
- Indoeuropeos y no Indoeuropeos en la Hispania Prerromana, Salamanca: Universidad, 2000
- The inscription of Cabeço das Fráguas revisited. Lusitanian and Alteuropäisch populations in the West of the Iberian Peninsula Transactions of the Philological Society vol. 97 (2003)
- Koch, John T (2010). Celtic from the West Chapter 9: Paradigm Shift? Interpreting Tartessian as Celtic. Oxbow Books, Oxford, UK. pp. 292–293. ISBN 978-1-84217-410-4.
- Cólera, Carlos Jordán (March 16, 2007). "The Celts in the Iberian Peninsula:Celtiberian". e-Keltoi 6: 749–750. Retrieved 16 June 2010.
- Koch, John T (2011). Tartessian 2: The Inscription of Mesas do Castelinho ro and the Verbal Complex. Preliminaries to Historical Phonology. Oxbow Books, Oxford, UK. pp. 1–198. ISBN 978-1-907029-07-3.
- A Swadesh list of the modern Celtic languages
- Celtic Congress
- Celtic League (political organisation)
- Continental Celtic languages
- Language families and languages
- Ball, Martin J. & James Fife (ed.) (1993). The Celtic Languages. London: Routledge. ISBN 0-415-01035-7.
- Borsley, Robert D. & Ian Roberts (ed.) (1996). The Syntax of the Celtic Languages: A Comparative Perspective. Cambridge: Cambridge University Press. ISBN 0521481600.
- Cowgill, Warren (1975). "The origins of the Insular Celtic conjunct and absolute verbal endings". In H. Rix. Flexion und Wortbildung: Akten der V. Fachtagung der Indogermanischen Gesellschaft, Regensburg, 9.–14. September 1973. Wiesbaden: Reichert. pp. 40–70. ISBN 3-920153-40-5.
- Celtic Linguistics, 1700–1850 (2000). London; New York: Routledge. 8 vols comprising 15 texts originally published between 1706 and 1844.
- Forster, Peter; Toth, Alfred (July 2003). "Toward a phylogenetic chronology of ancient Gaulish, Celtic, and Indo-European". Proc. Natl. Acad. Sci. U.S.A. 100 (15): 9079–84. Bibcode:2003PNAS..100.9079F. doi:10.1073/pnas.1331158100. PMC 166441. PMID 12837934.
- Gray, Russell D.; Atkinson, Quintin D. (November 2003). "Language-tree divergence times support the Anatolian theory of Indo-European origin". Nature 426 (6965): 435–39. Bibcode:2003Natur.426..435G. doi:10.1038/nature02029. PMID 14647380.
- Hindley, Reg (1990). The Death of the Irish Language: A Qualified Obituary. Routledge. ISBN 0-415-04339-5.
- Lewis, Henry & Holger Pedersen (1989). A Concise Comparative Celtic Grammar. Göttingen: Vandenhoeck & Ruprecht. ISBN 3-525-26102-0.
- McCone, Kim (1991). "The PIE stops and syllabic nasals in Celtic". Studia Celtica Japonica 4: 37–69.
- McCone, Kim (1992). "Relative Chronologie: Keltisch". In R. Beekes, A. Lubotsky, and J. Weitenberg (eds.). Rekonstruktion und relative Chronologie: Akten Der VIII. Fachtagung Der Indogermanischen Gesellschaft, Leiden, 31 August – 4 September 1987. Institut für Sprachwissenschaft der Universität Innsbruck. pp. 12–39. ISBN 3-85124-613-6.
- McCone, K. (1996). Towards a Relative Chronology of Ancient and Medieval Celtic Sound Change. Maynooth: Department of Old and Middle Irish, St. Patrick's College. ISBN 0-901519-40-5.
- Russell, Paul (1995). An Introduction to the Celtic Languages. Longman. ISBN 0582100828.
- Schmidt, K.H. (1988). "On the reconstruction of Proto-Celtic". In G. W. MacLennan. Proceedings of the First North American Congress of Celtic Studies, Ottawa 1986. Ottawa: Chair of Celtic Studies. pp. 231–48. ISBN 0-09-693260-0.
- Schrijver, Peter (1995). Studies in British Celtic historical phonology. Amsterdam: Rodopi. ISBN 90-5183-820-4.
- Schumacher, Stefan; Schulze-Thulin, Britta; aan de Wiel, Caroline (2004). Die keltischen Primärverben. Ein vergleichendes, etymologisches und morphologisches Lexikon (in German). Innsbruck: Institut für Sprachen und Kulturen der Universität Innsbruck. ISBN 3-85124-692-6.
|Wikisource has original works on the topic: Celtic languages|
|Wikimedia Commons has media related to Celtic languages.|
- Aberdeen University Celtic Department
- "Labara: An Introduction to the Celtic Languages", by Meredith Richard
- Celts and Celtic Languages
- What is necessary to decide if Lusitanian is a Celtic language?