Insular Celtic languages are the group of Celtic languages spoken in Brittany, Great Britain, Ireland, and the Isle of Man. All surviving Celtic languages are in the Insular group, including Breton, which is spoken on continental Europe in Brittany, France. The Continental Celtic languages, although once widely spoken in mainland Europe and in Anatolia, are extinct. Pritenic language, an ancestor of Pictish, was proposed as a part of Insular Celtic or a branch inside Early Brittonic.
Six Insular Celtic languages are extant (in all cases written and spoken) in two distinct groups:
Insular Celtic hypothesis
The Insular Celtic hypothesis is the theory that these languages evolved together in those places, having a later common ancestor than any of the Continental Celtic languages such as Celtiberian, Gaulish, Galatian, and Lepontic, among others, all of which are long extinct. This linguistic division of Celtic languages into Insular and Continental contrasts with the P/Q Celtic hypothesis.
The proponents of the Insular hypothesis (such as Cowgill 1975; McCone 1991, 1992; and Schrijver 1995) point to shared innovations among these – chiefly:
inflected prepositions
shared use of certain verbal particles
VSO word order
differentiation of absolute and conjunct verb endings as found extensively in Old Irish and less so in Middle Welsh (see Morphology of the Proto-Celtic language).
The proponents assert that a strong partition between the Brittonic languages with Gaulish (P-Celtic) on one side and the Goidelic languages with Celtiberian (Q-Celtic) on the other, may be superficial, owing to a language contact phenomenon. They add the identical sound shift (/kʷ/ to /p/) could have occurred independently in the predecessors of Gaulish and Brittonic, or have spread through language contact between those two groups. Further, the Italic languages had a similar divergence between Latino-Faliscan, which kept /kʷ/, and Osco-Umbrian, which changed it to /p/.
Pictish language is sometimes considered to be one of Brythonic languages or of a separate branch known as Pritenic. Some historians, such as George Buchanan in the 16th century, had suggested the Brythonic or P-Celtic language was a descendant of the Pictish language.
Under the Insular hypothesis, the family tree of the insular Celtic languages is thus as follows:
This table lists cognates showing the development of Proto-Celtic */kʷ/ to /p/ in Gaulish and the Brittonic languages but to /k/ in the Goidelic languages.
^ In Welsh orthography ⟨u⟩ denotes [ɨ] or [ɨ̞] in northern Welsh and [i] or [ɪ] in southern Welsh
A significant difference between Goidelic and Brittonic languages is the transformation of *an, *am to a denasalised vowel with lengthening, é, before an originally voiceless stop or fricative, cf. Old Irish éc "death", écath "fish hook", dét "tooth", cét "hundred" vs. Welsh angau, angad, dant, and cant. Otherwise:
the nasal is retained before a vowel, i̯, w, m, and a liquid:
Old Irish: ben "woman" (< *benā)
Old Irish: gainethar "he/she is born" (< *gan-i̯e-tor)
Old Irish: ainb "ignorant" (< *anwiss)
the nasal passes to en before another n:
Old Irish: benn "peak" (< *banno) (vs. Welsh bann)
Middle Irish: ro-geinn "finds a place" (< *ganne) (vs. Welsh gannaf)
the nasal passes to in, im before a voiced stop
Old Irish: imb "butter" (vs. Breton aman(en)n, Cornish amanyn)
Old Irish: ingen "nail" (vs. Old Welsh eguin)
Old Irish: tengae "tongue" (vs. Welsh tafod)
Old Irish: ing "strait" (vs. Middle Welsh eh-ang "wide")
Insular Celtic as a language area
In order to show that shared innovations are from a common descent it is necessary that they do not arise because of language contact after initial separation. A language area can result from widespread bilingualism, perhaps because of exogamy, and absence of sharp sociolinguistic division.
Ranko Matasović has provided a list of changes which affected both branches of Insular Celtic but for which there is no evidence that they should be dated to a putative Proto-Insular Celtic period. These are:
Phonological changes
The lenition of voiceless stops
Raising/i-affection
Lowering/a-affection
Apocope
Syncope
Morphological changes
Creation of conjugated prepositions
Loss of case inflection of personal pronouns (historical case-inflected forms)
Creation of the equative degree
Creation of the imperfect
Creation of the conditional mood
Morphosyntactic and syntactic
Rigidisation of VSO order
Creation of preposed definite articles
Creation of particles expressing sentence affirmation and negation
Creation of periphrastic construction
Creation of object markers
Use of ordinal numbers in the sense of "one of".
Absolute and dependent verb
The Insular Celtic verb shows a peculiar feature unknown in any other attested Indo-European language: verbs have different conjugational forms depending on whether they appear in absolute initial position in the sentence (Insular Celtic having verb–subject–object or VSO word order) or whether they are preceded by a preverbal particle. The situation is most robustly attested in Old Irish, but it has remained to some extent in Scottish Gaelic and traces of it are present in Middle Welsh as well.
Forms that appear in sentence-initial position are called absolute, those that appear after a particle are called conjunct (see Dependent and independent verb forms for details). The paradigm of the present active indicative of the Old Irish verb beirid "carry" is as follows; the conjunct forms are illustrated with the particle ní "not".
In Scottish Gaelic this distinction is still found in certain verb-forms across almost all verbs (except for a very few). This is a VSO language. The example given in the first column below is the independent or absolute form, which must be used when the verb is in clause-initial position (or preceded in the clause by certain preverbal particles). Then following it is the dependent or conjunct form which is required when the verb is preceded in the clause by certain other preverbal particles, in particular interrogative or negative preverbal particles. In these examples, in the first column we have a verb in clause-initial position. In the second column a negative particle immediately precedes the verb, which makes the verb use the verb form or verb forms of the dependent conjugation.
The verb forms in the above examples happen to be the same with any subject personal pronouns, not just with the particular persons chosen in the example. Also, the combination of tense–aspect–mood properties inherent in these verb forms is non-past but otherwise indefinite with respect to time, being compatible with a variety of non-past times, and context indicates the time. The sense can be completely tenseless, for example when asserting that something is always true or always happens. This verb form has erroneously been termed 'future' in many pedagogical grammars. A correct, neutral term 'INDEF1' has been used in linguistics texts.
In Middle Welsh, the distinction is seen most clearly in proverbs following the formula "X happens, Y does not happen" (Evans 1964: 119):
Pereid y rycheu, ny phara a'e goreu "The furrows last, he who made them lasts not"
Trenghit golut, ny threingk molut "Wealth perishes, fame perishes not"
Tyuit maban, ny thyf y gadachan "An infant grows, his swaddling-clothes grow not"
Chwaryit mab noeth, ny chware mab newynawc "A naked boy plays, a hungry boy plays not"
The older analysis of the distinction, as reported by Thurneysen (1946, 360 ff.), held that the absolute endings derive from Proto-Indo-European "primary endings" (used in present and future tenses) while the conjunct endings derive from the "secondary endings" (used in past tenses). Thus Old Irish absolute beirid "s/he carries" was thought to be from *bʰereti (compare Sanskrit bharati "s/he carries"), while conjunct beir was thought to be from *bʰeret (compare Sanskrit a-bharat "s/he was carrying").