The Celtic languages are a branch of the Indo-European languages today spoken on the fringes of northwestern Europe, including Irish, Welsh, and Scottish Gaelic. The ancestor of these languages was originally spoken by an ethnic group who are called Celts, who may or may not be related to present-day speakers of Celtic languages. Today some people in Britain, Ireland, France, Spain, and elsewhere self-identify as Celts, but when it comes to saying what a Celt is, a huge amount of hypothesis, guesswork, and pseudohistory is involved.
The Celtic regions are generally considered to be Scotland, Ireland, Wales, the Isle of Man, Cornwall, and Brittany; Galicia and Asturias in northwest Spain and parts of Portugal are sometimes also included. At their widest extent, Celtic languages were spoken through much of Europe — through France, Switzerland, Austria, and into the Balkans and Anatolia, but most of that over was 2000 years ago. Scientists try to understand the history of the Celts based on archaeology, critical reading of questionable literary sources, genetic studies of populations, and comparative linguistics, but none of these can really tell who a people were, where they lived, what religion they practiced, their opinion on patriarchy vs matriarchy, or how they self-identified. There is little evidence for the existence of Celts as a distinct race or ethnic group, and recent genetic studies suggest present-day Celts are no more closely related to each other than to neighbouring non-Celts. Despite this, the Celts have become a magical super-race for everybody from Wiccans to white nationalists to a variety of more moderate local independence movements.
Since the 19th century interest in Celtic languages and culture has been tied in with nationalisms (Scottish Nationalists and Scottish Gaelic, Cornish nationalists and the Cornish language, and so on). Such nationalism often involves nationalist pseudohistory, including claims to being the original inhabitants of their land, stories of ancient origins, claims to victimhood or military might, and pretence of being different from or better than neighbours — even if there is little difference between the so-called Celtic parts of the UK and the putatively Anglo-Saxon. Awareness of the history of Celtic languages has also promoted Pan-Celticism, an idea that there should be solidarity, commonality, and perhaps some measure of political union among some or all the Celtic peoples of Europe.
Despite the lack of knowledge of older Celtic culture, there have been frequent and imaginative attempts to revive Celtic religious traditions. There is very little knowledge of Celtic culture in the pre-Christian era, and even the Celtic Christian Church is shrouded in romanticism and woo. It also doesn't help that the Celtic revival in Scotland was associated with a number of prominent hoaxes, such as Ossian and the Vestiarium Scoticum.
- 1 Celtic languages
- 2 Celtic religion and culture
- 3 Theories of Celtic origin
- 4 Celtic nationalism
- 5 Other fringe theories
- 6 Pan-Celticism
- 7 Spelling reform
- 8 See also
- 9 Notes
- 10 References
Today, the most widely spoken Celtic languages are Welsh and Irish, with Breton, Scottish Gaelic, and Shelta having smaller populations, and traces of Cornish and Manx among enthusiasts. There are few, if any, monolingual speakers of the Celtic languages, but some are still spoken as first languages (often in rural communities), and they are learnt as second languages in far larger numbers by the inhabitants of the relevant nations.
There is little evidence of the earliest forms of Celtic, which must be reconstructed using the process of comparative linguistics. The earliest inscriptions are the Lepontic from northern Italy and around Lugano, Switzerland, from around 600 BCE. Such early sources offer few words other than proper names and little evidence of grammar. Before the Romans and the Germanic tribes, Celtic languages were probably spoken over much of Europe, from Turkey to Iberia, but unfortunately they left little evidence. Notable are Lepontic, the oldest attested from the 6th century BCE; the Northwestern Hispano-Celtic (or Celtiberian) languages spoken in northern Portugal and northwestern Spain; and the Gaulish languages, chiefly associated with modern-day France (which the Romans called Gaul). The earliest substantial texts date from around 600 AD; this is maybe 1000 years after the origin of the Celtic languages and far from their presumed starting-place, leaving a lot of space for guesswork.
Among present-day languages the main division is between Goidelic and Brittonic. The Godeilic languages have their origin in Ireland, where an early form was spoken by 1 CE, although the first short inscriptions are from the 3rd or 4th century CE, with written texts in Old Irish appearing as marginal glosses from the 6th century. This became Middle Irish then Modern Irish, while contact and/or settlement in the west of Scotland led to the establishment of Scottish Gaelic as separate language. Likewise, Manx was developed as a language from the Irish spoken by Irish settlers on the Isle of Man, very roughly 1000 AD. Shelta is a related language spoken by Irish travellers, which appears to have been derived from a mix of Irish and some other language. Scottish Gaelic should not be confused with Scots, which is a Germanic language closely related to English.
The Brittonic (or Brythonic) languages have their root in the hypothesised protolanguage Common Brittonic, the language of most of Britain prior to the Roman invasion in 43 CE. As the Romans and later invaders pushed these people to the edges of Britain and into northern France, Brittonic became separate languages: Welsh, Cornish, the Breton language of Brittany, and the extinct Cumbric language of northwest England and southern Scotland. An alternative division to Brittonic and Goidelic is between P-Celtic (Brittonic and Gaulish) and Q-Celtic (Goidelic and Celtiberian). The Pictish language, spoken in parts of northern and northeastern Scotland before about 1000 CE, might have been Brittonic too.
Celtic religion and culture
There is a desire among some Celtic aficionados to reconstruct and restage the rituals of Celtic religion: hopefully not the ones involving human sacrifice, but at least those involving dancing round a bonfire while drunk.
Celtic art, especially tattoos, have recently enjoyed a popularity well beyond other aspects of Celtic culture. Celtic art historically incorporated a wide range of things: the La Tène art of central Europe from around 500 BCE; the insular art of north British and Irish monasteries and manuscripts from the first millennium CE; and even Pictish art, notwithstanding the uncertainty of whether Picts were Celts.
Today, Celtic art primarily refers to ornate knotwork, popular a few years ago in tattoos. The Celtic cross is a type of Christian cross with a ring around where the horizontal and vertical meet; it is usually decorated with elaborate knots and swirls.
Theories of Celtic origin
There are various elaborate theories of the origin of the Celtic people. Many of these predate modern understandings of the Celtic languages, as well as modern anthropology, linguistics, historical method, and just about everything else rational. In the 18th and 19th centuries, this was typically based on descent from antiquity, where the monarchs of your chosen Celtic region can be traced back in an unbroken chain to the Trojan War or Garden of Eden. Other theories are slightly more sophisticated.
Academic theories attempt to place the origin of the Celtic languages in specific cultures in central Europe, which often resolves to an attempt to pair pottery with language. The better-regarded theories link the original Celts with either:
- Urnfield culture, late bronze age (c. 1300-750 BCE), from SE France through Italy, S and W Germany, and into southern Poland and the northern Balkans.
- Hallstatt culture, early iron age (c. 8th-6th century BCE), centred in Austria.
- La Tène culture, an iron age culture that developed out of the Hallstatt around 450 BCE.
Between 450 BCE and 375 BCE, these Celts spread widely through Europe, or at least their language did (it isn't clear who they displaced, but feel free to mention the Basques). In the late Roman Republic, there were powerful Celtic communities in northern Italy and France. But soon after this, the growing Roman empire and then Germanic tribes from northern Europe removed Celtic languages from the map, except in parts of Britain, Ireland, and Brittany. It's clear that these rapid changes weren't entirely due to population movements, but equally it's not clear exactly how they did happen.
There are a few mentions of the Celts in classical Greek and Roman sources, generally placing them in what is now southern France and northern Spain. Herodotus writing in the 5th century BCE mentions the Keltoi near the source of the Danube (he seems to have believed the Danube rose near the Pyrenees) and describes them as living far in the west. Feel free to point out the many gross geographical inaccuracies in Herodotus if you want to claim an alternative origin. Hecataeus mentioned Massalia (Marseilles) as a Celtic city around 500 BCE. The Greek historian Ephorus of Cyme writing around around 350 BCE is only known from references in other people's books but it seems that he claimed most of Iberia was inhabited by Celts. Later, Caesar mentioned that the Gauls living south of the Seine (in what is now central France) called themselves Celts. Strabo (c. 64 BCE - c. 24 CE) mentioned them as living in what is now northern Spain and the region described by Caesar.
Ideas of some kind of migration come from the development of artistic motifs and the movement of manufactured objects from central Europe to the fringes of northwestern Europe. This movement may partly be due to trade and diffusion of cultural ideas but probably also involved migrating people carrying artifacts and knowledge of techniques. From this basic knowledge came a myth, popular in the Celtic Revival in the 19th century, that the Celts were an advanced warlike people who arose somewhere like Switzerland or Austria and conquered most of Europe prior to the Romans, getting as far as Ireland. Even if the language came from central Europe (which is possible), more recent research suggests the population did not: the people of what are now called Celtic lands were not a distinctive race or ethnic group: modern genetic evidence is discussed below.
Alternative, even less plausible theories seek to maximise the ancientness of the Celts, linking them to the Beaker culture as far back as 2800 BCE, and placing them in the far west of Europe, possibly Iberia (suspiciously, this is particularly popular among Spanish scientists).
There is a separate theory proposed by Bryan Sykes of Oxford University based on genetic analysis that Britain's original inhabitants were seafarers from Iberia who may have reached Britain around 5000-4000 BCE. These people were emphatically not Celts and certainly did not speak a Celtic language. Stephen Oppenheimer, who rejects a significant Celtic influence on the UK population, has posited an even older Iberian origin, suggesting British people's ancestors arrived from Spain around 14000 BCE speaking something akin to Basque.
It's not unlikely that Britain was colonised by seafarers. Whether or not they spoke Basque is something we can never really know (well, obviously they didn't speak modern Basque). Since Basque is a linguistic isolate with no known related languages other than the extinct Aquitanian, this is unlikely to ever be proven.
It's a well known pseudofact in pseudohistory that everybody is member of at least one of the ten lost tribes of Israel. The Celts are alleged to have descended from the tribe of Dan, who were known for their seafaring prowess. This can be seen by the fact that the harp is the symbol of Ireland and also the favorite instrument of King David. Seriously, no.
There are attempts to understand pre-Celtic civilisations and find traces of them in the proto-Celtic languages, pre-Old Irish. Hypothetical loanwords taken into early Celtic include a word for sheep or goat, cognate of the Old Irish molt and a hypothetical Gaulish ancestor of the French mouton; also the Irish brocc=badger, anglicised as "brock". Suggestively, a Middle Irish word for young woman, ainder, resembles the Basque andere, meaning woman. It could all be coincidence, but it's a fun game.
Recently technology has allowed large-scale comparison of genetics between different populations. Such studies can indicate the commonality or difference between two or more groups, even if they can't tell you anything precise about where people lived or what they did. Studies don't indicate a common Celtic population shared between Scotland, Ireland, and Wales.
A study published in Nature in 2015 rejected claims that the Celts formed a distinctive group: the study of middle-aged white people showed that there were genetic differences between different regions of the UK, but Scots and Cornish people had more in common with English populations than with other Celtic groups. It suggested that the Anglo-Saxon invaders mixed with the native Britons rather than displacing them to the Celtic fringes. It also showed that people in the north of England are closer to the Scots than to the south of England, and the populations of north and south Wales are rather different from each other. This broadly matches earlier genetic studies which suggest Britain's population has been there far longer than a Celtic origin would suggest (with the Proto-Celtic language no earlier than 1250 BCE.
Another study suggested that the British Isles' population mostly arrived between 15000 and 7500 years ago, long before the Celts. None of this is conclusive, but growing evidence shows a distinctively Celtic race is unlikely.
Language and nationalism
There are many types of nationalism. They may be based on race, on ethnicity (which often will include a particular native language and its literature as part of a wider culture), or on civic nationalism which focuses on the current inhabitants of a given place. Additionally, while nationalism is normally associated with political independence and nation-states, its believers may prefer some other kind of autonomy or association. Most nationalists have focused on a mix of cultural and political activity but on the fringes there have been violent groups dedicated to driving out the English invaders (i.e. burning down retirement cottages).
There was a strong sense particularly in 19th and early 20th century nationalist thought that a nation required a language and vice versa. Thus while the Irish language had been largely extinguished by centuries of English and British rule, its revival in the late 19th and early 20th century was intertwined with the birth of Ireland as an independent nation. Similar phenomena can be seen in non-Celtic places such as Israel's revival of Hebrew as a national language, or the deprecation of English and French in post-colonial Africa. However, the promotion of a regional language may alternatively be associated with a cultural pride that falls short of outright nationalism, and not everybody who speaks Scottish Gaelic, even as an adult learner, is a Scottish nationalist.
It should not be assumed that the realm of a language matches the modern idea of a nation's borders. This is contentious in Scotland, where some nationalists claim that everybody spoke Gaelic until the English made them stop, and unionists seek to minimise the role of Gaelic to a few barbarians outside civilisation. As in most things the reality is more complex, with Cumbric lasting well beyond 500 CE (perhaps as late as 1000 CE) in the south, Anglic languages related to Scots and English spoken in southeast Scotland by about 600 CE when Gaelic was still at its infancy in the west, Norse-speaking invaders in the far north and islands, Picts speaking something uncertain, Irish in the far southwest of Scotland (e.g. Kintyre) where until recently it was much easier to sail to Ireland than travel to the rest of Scotland, and French, Polish, et al.
Before substantial written records, which were in scarce supply even 1000 years ago, the main evidence is in inscriptions and place names. However, if you followed this method too literally you might guess that everybody in Europe was speaking Latin as a first language until around 1950: inscriptions may be in religious, learned, courtly, or invaders' languages, rather than the demotic language actually spoken by most people. Furthermore, it is hard to trace the origin of place names where multiple languages encountered each other and transfer of word-elements was common but evidence is limited (for example in Scotland, crag/craig is found in both Gaelic and Scots, while the element dal- was originally Brittonic/Cumbric but adopted into Gaelic and used in many Gaelic place names).
While Scottish and Irish nationalism are well-established forces, albeit with significant areas of debate, others attract wholesale skepticism. Principally, Cornish nationalism. The vagueness of Celtic tradition can be seen in how enemies such as Brittany and France, or England and the Celtic fringes, can simultaneously call upon a Celtic past.
The Irish language, and Celtic culture with its history, myths, and legends were central to Irish nationalism for hundreds of years. Despite this, historians and archaeologists have questioned the importance of distinctively Celtic culture in the island's past: the idea of Ireland as Celtic began in the 19th century. There's a lack of archaeological evidence of a Celtic invasion of Ireland or a sudden change of culture that would accompany such a takeover. Absent evidence of Celtic culture, there is certainly a mass of Celtic language literature dating back to the 1st millennium CE, but most of that was connected with early Christianity rather than with indigenous pre-Christian culture (e.g. St Bride/Bridget clearly has some relationship with pre-Christian goddesses but exactly what is contested).
Scottish nationalism is not exclusively Gaelic: one of the great pioneers of Scottish nationalism, the poet Hugh MacDiarmid, was an innovator in the use of the Lowland Scots language, and others like Lewis Spence celebrated Celtic culture while actually writing in Scots and English. But often the Gaelic language is invoked by Scottish nationalists, both as a badge of national identity and as an example of something crushed by the evil English. For the extremist nationalist organisation Siol nan Gaidheal, Gaelic is central to Scottish identity and the soul of Scotland.
Scottish nationalism based on Celtic identity requires a rather strained and convoluted view of Scottish history. Well before Scotland ceased being independent in 1707, the Gaelic language had withered, in part due to hostile treatment by lowland Scots who regarded Highlanders as ignorant savages. The decline of Gaelic in Scotland is often dated to the reign of Malcolm III of Scotland (1058 to 1093) whose wife St Margaret was English; by the mid 14th century the Insular Germanic language now called Scots was the main language of government and administration, as well as of the writers of the Scottish Renaissance from the late 15th century; by then Gaelic was known as Yrisch (Irish) or Erse and viewed as a foreign language.
The relationship with Irish is a source of complex emotions: it seems to prove a deep bond, while relegating Scottish Gaelic to secondary status (you might compare the relationship of the Japanese to the Chinese over their writing system and other traditions[note 1]). This is obviously a problem for ultra-Protestants who hate Catholic Ireland, but the whole point of nationalism is to assert that your nation is unique. As a result some nationalists are keen to exaggerate Scottish Gaelic's status as a single unified language, but it has regional variation, and it is likely that in the past it formed a continuum with Irish Gaelic. The conclusion from this might be to question whether Scottish Gaelic is an independent language, but most languages (even those tightly policed by a national academy) are ever-changing, contain numerous foreign influences, and shade into their neighbours. Hence Gaelic should be preserved on its own merits, including a strong tradition of 20th century poetry, not for nationalist reasons.
The Welsh language lasted better as a first language than either Scottish Gaelic or Irish. Despite this, a belief in Welsh independence is still a minority idea, supported by less than 10% of the population. The language is largely restricted to the rural north, which means it is problematic for some Welsh people in the south. Nonetheless, the Welsh language is now compulsory in school up to the age of 16; in 2011, 19% of the population spoke Welsh, a slight decline from 2001.
As well as the mainstream pro-independence party Plaid Cymru there has long been a violent fringe. There have been militant movements such as William Julian Cayo-Evans's paramilitary Free Wales Army and violent anti-"settler" campaigns involving small groups such as Meibion Glyndŵr (Sons of Glyndŵr); but there has been no real violence since the end of the 1990s.
The idea of Cornish independence is a fringe one, and most Cornish nationalists focus on greater autonomy within the UK. Cornish culture is bolstered by the Institute of Cornish Studies at the University of Exeter (while Exeter is across the border in Devon, England, the Institute is near Penryn, Cornwall). The centre-left nationalist party Mebyon Kernow makes use of the Cornish language; its rival is the centre-right but less successful Cornish Nationalist Party.
Cornish nationalists don't often make the media, but they got some publicity when they campaigned against the sale of England flags in Cornwall during the 2010 Football World Cup.
Even more fringe than the mainstream are the paramilitaries, such as the Cornish National Liberation Army, which targeted restaurants owned by English celebrity chefs Rick Stein and Jamie Oliver; the CNLA claimed 30 members in 2007. In the 1970s, the Free Cornish Army declared Cornish independence; this proved to be a prank by students from the University of Plymouth, although it's not really much less serious than the CNLA.
Unvaniezh Demokratel Breizh campaigns for autonomy for Brittany, often in coalition with the Greens or Socialists. Breton nationalism is largely focused on devolution and language rights, but there has been a campaign to seize the French province of Loire-Atlantique (peaceably, of course). Agence Bretagne Presse was founded in 2003 and publishes news stories on the Celtic nations in English, French and Breton.
The Isle of Man has a high degree of autonomy, but nonetheless has occasionally had active nationalist movements wanting even more. The Manx Language Society was founded in 1899 influenced by movements in Ireland. In the early 20th century there was a syndicalist movement which was brutally suppressed. Mec Vannin was founded in 1964, seeking greater autonomy and language rights, which have now largely been granted.
Asturias and Galicia in northwestern Spain still assert a Celtic identity. This includes an interest in druidism alongside the region's Christian traditions, and an interest in Celtic matriarchy.
While the Bretons in Brittany are widely considered a Celtic race and their language is Celtic, there is also a use of France's pre-Roman Gaulish traditions in French nationalism. An example is the French president François Mitterrand invoking the victory of Vercingetorix against the Romans as a symbol of French national unity.
While Celtic nationalism in the British Isles typically exists in opposition to the English, even England can call on Celtic nationalist heroes, such as Queen Boudica of the Iceni, who fought against the Romans; in subsequent centuries she was identified with later British monarchs including Elizabeth I and Victoria.
White and European nationalism
Celtic tradition and art has also been called upon by white nationalists, who have used the Celtic cross and the old Norse/Celtic Sonnenrad as emblems. The simpler form of Celtic cross (four equal limbs with a circle round the centre), known as a sun cross or wheel cross, was used by Nazis in the 1930s and 1940s and more recently has been used by neo-Nazis, the Ku Klux Klan, and others. Various people including George Orwell have found a racist taint to Celtic nationalism, which he distinguished from Scottish, Welsh or Irish nationalism. (Celtic white nationalism should not be confused with pan-Celticism; the latter seeks to unite the Celts against the English, French, Spanish, and other white races, but Celtic white nationalists assume all western and central Europe was once Celtic.)
Other fringe theories
The racially inferior Celt
A belief that Celtic Highlanders and Irish people were in some way racially inferior to the rest of Britain had a long history. In the 19th century, the [[poverty[[ of people in the north of Scotland and Ireland, and specific events such as the mid-19th century potato famines in Ireland and northwest Scotland were explained on the basis that the Celts were inferior to the Anglo-Saxon and Teuton who inhabited the rest of Britain (including northeast Scotland). This theory is flawed in many ways: the Celts weren't a distinct race; the problems they faced could be explained by history, climate and economics (they farmed potatoes because they lived in the coldest or wettest parts of Britain); there was no attempt at real [[scientific[[ comparison.
Scottish Gaelic is autochthonous
A few people question the dominant theory of Goidelic origins which holds that the Scots and the Scottish Gaelic language originated in Ireland. These people suggest that there is no evidence of invasion, mass migration, or other spread from Ireland to Scotland, and therefore Scottish Gaelic and Irish sprung up alongside each other at opposite sides of the North Channel. This belief is found in some extremist Scottish nationalist circles and seems to be the position of Siol nan Gaidheal, who suggest that the Brittonic Celtic languages are descended from Goidelic, which itself developed in Argyll rather than being brought over from Ireland. This seems an instance of the common pseudohistorical phenomenon where nationalists want to claim they are the original inhabitants, speaking the original language, and that they predate all their neighbours.
Similar to this, it was formerly believed by some (mainly Celtic nationalists) that the Breton-speakers of Brittany were remnants of the original population of France (hence indigenous Celts or Gauls). It is now known that the Breton language is descended from ancient Britons who fled across the English Channel to France some time after 500 CE.
Britain was never Celtic
The geneticist Stephen Oppenheimer has suggested that Britain's population was not substantially Celtic ever (either in language or population), pointing to the lack of Celtic influence in the English language and evidence of pre-Roman trade with Germanic tribes. This theory requires that the English language is far older than conventionally believed, splitting with other west Germanic languages well before 1 BCE — despite the lack of any inscription or other record. Such theories, based on the absence of evidence and the idea that when Tacitus was speaking about Gauls he really meant Belgae, are by their nature tendentious though hard to falsify.
Gaelic is better than Scots
This is a nationalist meme holding that Scottish Gaelic is a proper language and Scots is just a bastard version of the English language of Scotland's English oppressors. Ironically it's the mirror image of the theory that Scottish Gaelic isn't a real language but is just a bastardisation of Irish (this has few modern-day adherents but was mainstream in the Renaissance/early modern period). Currently Gaelic has higher legal status than Scots in Scotland. Meanwhile in Northern Ireland, Unionists have said that if Irish is recognised as an official language, Ulster Scots should be too. In the world of linguistics, there's no clear way of deciding what is a language and what is a dialect or other form, so the debate can run endlessly.[note 2]
Pan-Celticism is a belief in a commonality among the Celtic people of Britain or Europe, by some definition of Celtic. It often resolves into the Scottish, Irish, and Welsh ganging up against the English — which is nonsensical in terms of population genetics or language, as pretty much all of Great Britain spoke Celtic languages once, and outside north Wales, northwest Scotland and Gaeltacht in Ireland, most stopped speaking Celtic languages a long time ago.
One of the dominant organisations is the Celtic League, founded in 1961. It controversially rejected a Galician application for membership, although there is a Patagonian branch (Argentina has a small Welsh-speaking population). Its predecessors include the Celtic Congress which was founded in 1901, which continues as a largely academic body focused on providing research funding.
While the preservation of minority languages is an important goal, it's unclear that the Celts have anything else in common, either in religion, politics, culture, or genetics. It is sometimes suggested that they shared an experience of being crushed by the English (except the Bretons, who were crushed by the French), but that requires rather a simplistic view of history that ignores all the other people crushed by the English, and the role of the native population (e.g. lowland Scottish people) in crushing Celtic speakers.
Some of the Celtic languages, particularly Scottish Gaelic, have a somewhat arcane orthography, far away from a one-to-one mapping between letter and sound (or letter and phonological unit). This isn't the place to debate the merits of proposals for reform, but merely to note that a small number of people get very very intense about what can only ever be an arbitrary decision regarding a language that "few can read, and nobody can write".
- The Japanese and Chinese languages however are unrelated, as the Japanese only borrowed the Chinese writing system.
- Degree of mutual intelligibility is used do decide dialect vs. language, but it's arbitrary deciding what percentage of intelligibility makes a dialect vs. language, and there is the issue of dialect continua where dialects on the far geographic ends of each other are mutually unintelligible.
- See the Wikipedia article on Celts.
- DNA study shows Celts are not a unique genetic group, Pallab Ghosh, BBC, 18 Mar 2015
- See the Wikipedia article on Pan-Celticism.
- See the Wikipedia article on Lepontic language.
- See the Wikipedia article on Proto-Celtic language.
- See the Wikipedia article on Celtic art.
- Herodotus, The Histories, Exploring Celtic Civilizations, ed. Michael Newton, University of North Carolina
- Celtic Culture, ABC-CLIO, vol 1, p 707
- Myths of British ancestry, Stephen Oppenheimer, Prospect Magazine, Oct 21, 2006
- Commentaries on the Gallic War, Julius Caesar, Exploring Celtic Civilizations, ed. Michael Newton, University of North Carolina
- Strabo: Geography, Exploring Celtic Civilizations, ed. Michael Newton, University of North Carolina
- See the Wikipedia article on Celts.
- Celts descended from Spanish fishermen, study finds, The Independent, 20 Sep 2006
- A United Kingdom? Maybe, New York Times, 6 March 2007
- Are the Celts one of the ten lost tribes of Israel?, Irish Central
- See the Wikipedia article on Goidelic substrate hypothesis.
- Opinion: Our Celtic identity might not be what we think it is, Caomhín De Barra, The Journal (Ireland), 26 Aug 2018
- Gaelic Civilisation: The Gaelic Soul of Alba, Sion nan Gaidheal website, accessed 11 Jan 2019
- Gaelic, Sion nan Gaidheal website, accessed 11 Jan 2019
- See the Wikipedia article on Scottish Gaelic.
- See the Wikipedia article on Welsh independence.
- See the Wikipedia article on Welsh language.
- See the Wikipedia article on Meibion Glyndŵr.
- See the Wikipedia article on Cornish nationalism.
- Cornish nationalists protest against World Cup England flags, Metro, 13 May 2010
- See the Wikipedia article on Cornish National Liberation Army.
- See the Wikipedia article on Celtic League.
- Celtic Nationalism, An Sionnach Fionn
- A brief history of manx nationalism, Agence Breton Presse
- Galicia’s disputed Celtic heritage, The Economist, 9 May 2017
- The Modern Celts of Northern Spain, Beebe Bahrami, Expedition, Penn Museum, Volume 45Issue 12003
- "Our Ancestors the Gauls": Archaeology, Ethnic Nationalism, and the Manipulation of Celtic Identity in Modern Europe, Michael Dietler, American Anthropologist, New Series, Vol. 96, No. 3 (Sep., 1994), pp. 584-605
- See the Wikipedia article on Boudica.
- Deconstructing the symbols and slogans spotted in Charlottesville (August 18, 2017) The Washington Post.
- General Hate Symbols: Celtic Cross, Anti-Defamation League, accessed 19 Feb 2019
- George Orwell on Celtic Nationalism, Graham Smith, BBC Blogs, 22 Feb 2011
- "A Country Emptied: review of The Scottish Clearances: A History of the Dispossessed 1600-1900 by T.M. Devine", Ian Jack, London Review of Books, Vol. 41 No. 5, 7 March 2019, pages 19-22
- Were the Scots Irish?, Ewan Campbell, Electric Scotland
- Dunadd, Sion nan Gaidheal website, accessed 11 Jan 2019
- See the Wikipedia article on Breton language.
- Toward a phylogenetic chronology of ancient Gaulish, Celtic, and Indo-European, Peter Forster and Alfred Toth, PNAS July 22, 2003 100 (15) 9079-9084; https://doi.org/10.1073/pnas.1331158100
- Scots and Ulster-Scots Are Not Languages, Whistling in the Wind, 11 Jan 2017
- Saving a language is one thing, but I'm saddened by Scotland going Gaelic, Ian Jack, The Guardian, 11 Dec 2010
- Ulster-Scots 'forgotten in some ways', BBC, 28 June 2017
- See the Wikipedia article on Pan-Celticism.
- See the Wikipedia article on Scottish Gaelic orthography.
- Critique of the "New" Gaelic Orthographic Conventions, Lloyd Leland, 1991