Proto-Celtic language

Proto-Celtic, or Common Celtic, is the hypothetical ancestral proto-language of all known Celtic languages, and a descendant of Proto-Indo-European. It is not attested in writing but has been partly reconstructed through the comparative method. Proto-Celtic is generally thought to have been spoken between 1300 and 800 BC, after which it began to split into different languages. Proto-Celtic is often associated with the Urnfield culture and particularly with the Hallstatt culture. Celtic languages share common features with Italic languages that are not found in other branches of Indo-European, suggesting the possibility of an earlier Italo-Celtic linguistic unity.

Proto-Celtic is currently being reconstructed through the comparative method by relying on later Celtic languages. Though Continental Celtic presents much substantiation for Proto-Celtic phonology, and some for its morphology, recorded material is too scanty to allow a secure reconstruction of syntax, though some complete sentences are recorded in the Continental Gaulish and Celtiberian. So, the main sources for reconstruction come from Insular Celtic languages with the oldest literature found in Old Irish and Middle Welsh, dating back to authors flourishing in the 6th century AD.

Dating

Proto-Celtic is usually dated to the Late Bronze Age, ca. 1200–900 BC.Koch, John T. (2020)
Celto-Germanic Later Prehistory and Post-Proto-Indo-European vocabulary in the North and West
, pp. 45–48. The fact that it is possible to reconstruct a Proto-Celtic word for 'iron' (traditionally reconstructed as ''*īsarnom'') has long been taken as an indication that the divergence into individual Celtic languages did not start until the Iron Age (8th century BC to 1st century BC); otherwise, descendant languages might have developed their own, unrelated words for the metal. However, Schumacher and Schrijver suggest a date for Proto-Celtic as early as the 13th century BC, the time of the Canegrate culture, in northwest Italy, and the Urnfield culture in Central Europe, implying that the divergence may have already started in the Bronze Age.

Sound changes from Proto-Indo-European

The phonological changes from Proto-Indo-European (PIE) to Proto-Celtic (PC) may be summarized as follows. The changes are roughly in chronological order, with changes that operate on the outcome of earlier ones appearing later in the list.

Late PIE

These changes are shared by several other Indo-European branches.
* *e is colored by an adjacent laryngeal consonant:
** eh₂, h₂e > ah₂, h₂a
** eh₃, h₃e > oh₃, h₃o
* Palatovelars merge into the plain velars:
** ḱ > k
** ǵ > g
** ǵʰ > gʰ
* Epenthetic *a is inserted after a syllabic sonorant if a laryngeal and another sonorant follow (R̥HR > RaHR)
* Laryngeals are lost:
** before a following vowel (HV > V)
** following a vowel in syllables before the accent (VHC´ > VC´)
** following a vowel before a consonant, or word finally, resulting in compensatory lengthening, thus (VHC > V̄C, VH# > V̄#)
** between plosives in non-initial syllables (CHC > CC)
* Two adjacent dentals become two adjacent sibilants (TT > TsT > ss)

Italo-Celtic

The following sound changes are shared with the Italic languages in particular, and are cited in support of the Italo-Celtic hypothesis.
* Dybo's rule: long close vowels are shortened (or a laryngeal is lost) before resonant + stressed vowel. Note that something like Dybo's rule seems to have also operated in Germanic (Old English wer < *wiHró-).
** īR´ / ? *iHR´ > iR´
** ūR´ / ? *uHR´ > uR´
* Possibly, post-consonantal laryngeals are lost when before pre-tonic close vowels:
** CHiC´ > CiC´
** CHuC´ > CuC´
* Development of initial stress, following the previous two changes. But note that this seems to have been an areal feature, shared, for example with the Indo-European Germanic languages and the non-Indo-European Etruscan language.
* Possibly, vocalization of laryngeals to *ī between a *CR cluster and consonantal *j (CRHjV > CRījV)
* Syllabic laryngeals become *a (CHC > CaC)
* Syllabic resonants before a voiced unaspirated stop become *Ra (R̩D > RaD)
* *m is assimilated or lost before a glide:
** mj > nj
** mw > w
* *p assimilates to *kʷ when another *kʷ follows later in the word (p...kʷ > kʷ...kʷ). But Matasovic points out that: A) this change may have occurred late in Celtic; B) it seems not to have operated on some words in Irish; and C) a very similar assimilation (though in reverse) also occurred in Germanic.

One change shows non-exact parallels in Italic: vocalization of syllabic resonants next to laryngeals depending on the environment. Similar developments appear in Italic, but for the syllabic nasals *m̩, *n̩, the result is Proto-Italic *əm, *ən (> Latin ''em'' ~ ''im'', ''en'' ~ ''in'').
* Word-initially, HR̩C > aRC
* Before voiceless stops, CR̩HT > CRaT
* CR̩HV > CaRHV
* CR̩HC > CRāC

Early PC

* Sequences of velar and *w merge into the labiovelars (it is uncertain if this preceded or followed the next change; that is, whether gw > b or gw > gʷ, but Schumacher 2004 argues on p. 372 that this change came first; moreover, it is also found in Proto-Italic, and thus arguably belongs to the previous section):
** kw > kʷ
** gw > gʷ
** gʰw > gʷʰ
* *gʷ merges into *b.
* Aspirated stops lose their aspiration and merge with the voiced stops (except that this counterfeeds the previous change, so *gʷʰ > *gʷ doesn't result in a merger; that is, the change ''*gʷʰ > *gʷ'' must crucially happen ''after'' the sound change ''gʷ > b'' has been completed):
** bʰ > b
** dʰ > d
** gʰ > g
** gʷʰ > gʷ
* *e before a resonant and *a (but not *ā) becomes *a as well (eRa > aRa): *ǵʰelH-ro > *gelaro > *galaro / *gérH-no > *gerano > *garano (Joseph's rule).
* Epenthetic *i is inserted after syllabic liquids when followed by a plosive:
** l̩T > liT
** r̩T > riT
* Epenthetic *a is inserted before the remaining syllabic resonants:
** m̩ > am
** n̩ > an
** l̩ > al
** r̩ > ar
* All remaining nonsyllabic laryngeals are lost.
* ē > ī
* ō > ū in final syllables
* Long vowels are shortened before a syllable-final resonant (V:RC > VRC); this also shortens long diphthongs. ( Osthoff's law)

Late PC

* Plosives become *x before a different plosive or *s (C₁C₂ > xC₂, Cs > xs)
* p > b before liquids (pL > bL)
* p > w before nasals (pN > wN)
* p > ɸ (except possibly after *s)
* ō > ā
* ey > ē (but not in Celtiberian or Lepontic)
* ew > ow
* uwa > owa

Examples

Phonological reconstruction

Consonants

The following consonants have been reconstructed for Proto-Celtic (PC):
:

Allophones of plosives

Eska has recently proposed that PC stops allophonically manifest similarly to those in English. Voiceless stop phonemes /t k/ were aspirated word-initially except when preceded by /s/, hence aspirate allophones ʰ kʰ And unaspirated voiced stops /b d ɡ/ were devoiced to t kword-initially.

This allophony may be reconstructed to PC from the following evidence:
* Modern Celtic languages like Welsh, Breton, and all modern Goidelic languages have such plosive aspiration and voice allophony already attested. (But there is no trace of this in Gaulish.)
* Several old Celtic languages (such as Old Irish, Old Welsh, and Lepontic) used letters for voiceless stop phonemes to write both voiceless stop phonemes and their voiced counterparts, especially non-word-initially. (But in the case of Lepontic, this is because the alphabet was derived from Etruscan, which has no voice contrasts in plosives.)
* The Celtiberian Luzaga's Bronze has the curious spelling of an accusative determiner ''sdam'', where the ''d'' is clearly meant to spell This implies that Celtiberian /d/ had a voiceless allophone .

Evolution of plosives

Proto-Indo-European (PIE) voiced aspirate stops *''bʰ'', *''dʰ'', *''gʰ/ǵʰ'', merge with *''b'', *''d'', *''g/ǵ'' in PC. The voiced aspirate labiovelar *''gʷʰ'' did not merge with *''gʷ'', though: plain *''gʷ'' became PC *''b'', while aspirated *''gʷʰ'' became *''gʷ''. Thus, PIE *''gʷen-'' 'woman' became Old Irish and Old Welsh ''ben'', but PIE *''gʷʰn̥-'' 'to kill, wound' became Old Irish ''gonaid'' and Welsh ''gwanu''.

PIE *''p'' is lost in PC, apparently going through the stages *''ɸ'' (possibly a stage * ʰ and *''h'' (perhaps seen in the name Hercynia if this is of Celtic origin) before being completely lost word-initially and between vowels. Next to consonants, PC *''ɸ'' underwent different changes: the clusters *''ɸs'' and *''ɸt'' became *''xs'' and *''xt'' respectively already in PC. PIE *''sp-'' became Old Irish ''s'' (''f-'' when lenited, exactly as for PIE *''sw-'') and Brythonic ''f''; while argues there was an intermediate stage *''sɸ-'' (in which *''ɸ'' remained an independent phoneme until after Proto-Insular Celtic had diverged into Goidelic and Brythonic), finds it more economical to believe that *''sp-'' remained unchanged in PC, that is, the change *''p'' to *''ɸ'' did not happen when *''s'' preceded. (Similarly, Grimm's law did not apply to *''p, t, k'' after *''s'' in Germanic, and the same exception occurred again in the High German consonant shift.)

:

In Gaulish and the Brittonic languages, the Proto-Indo-European * phoneme becomes a new * sound. Thus, Gaulish ''petuar os', Welsh ''pedwar'' "four", but Old Irish ''cethair'' and Latin ''quattuor''. Insofar as this new fills the gap in the phoneme inventory which was left by the disappearance of the equivalent stop in PIE, we may think of this as a chain shift.

The terms P-Celtic and Q-Celtic are useful for grouping Celtic languages based on the way they handle this one phoneme. But a simple division into P- / Q-Celtic may be untenable, as it does not do justice to the evidence of the ancient Continental Celtic languages. The many unusual shared innovations among the Insular Celtic languages are often also presented as evidence against a P- ''vs'' Q-Celtic division, but they may instead reflect a common substratum influence from the pre-Celtic languages of Britain and Irelan

or simply continuing contact between the insular languages; in either case they would be irrelevant to the genetic classification of Celtic languages.

Q-Celtic languages may also have in loan words, though in early borrowings from Welsh into Primitive Irish, was used by sound substitution due to a lack of a phoneme at the time:
*Latin ''Patricius'' " Saint Patrick"' > Welsh > Primitive Irish > Old Irish ''Cothrige'', later ''Pádraig'';
*Latin '' presbyter'' "priest" > early form of word seen in Old Welsh ''premter primter'' > Primitive Irish > Old Irish ''cruimther''.
Gaelic ''póg'' "kiss" was a later borrowing (from the second word of the Latin phrase ''osculum pacis'' "kiss of peace") at a stage where ''p'' was borrowed directly as ''p'', without substituting ''c''.

Vowels

The PC vowel system is highly comparable to that reconstructed for PIE by Antoine Meillet. The following monophthongs are reconstructed:
:

The following diphthongs have also been reconstructed:
:

Morphology

Nouns

The morphological (structure) of nouns and adjectives demonstrates no arresting alterations from the parent language. Proto-Celtic is believed to have had nouns in three genders, three numbers and five to eight cases. The genders were masculine, feminine and neuter; the numbers were singular, plural and dual. The number of cases is a subject of contention: while Old Irish may have only five, the evidence from Continental Celtic is considered rather unambiguous despite appeals to archaic retentions or morphological leveling. These cases were nominative, vocative, accusative, dative, genitive, ablative, locative and instrumental.

Nouns fall into nine or so declensions, depending on stem. There are *''o''-stems, *''ā''-stems, *''i''-stems, *''u''-stems, dental stems, velar stems, nasal stems, *''r''-stems and *''s''-stems.

*''o''-stem nouns

*''makkʷos'' 'son' (masculine) (Old Irish ''mac'' ~ Welsh, Cornish and Breton ''mab'')

However, Celtiberian shows -o- stem genitives ending in ''-o'' rather than ''-ī'': aualo " onof Avalos". Also note that the genitive singular does not match Proto-Indo-European's ''-osyo'', which would have yielded ''-osjo''.

*''dūnom'' 'stronghold' (neuter)

As in the masculine paradigm, the genitive singular does not match Proto-Indo-European's ''-osyo'', which would have yielded ''-osjo''.

*''ā''-stem nouns

E.g. *''ɸlāmā'' 'hand' (feminine) (Old Irish ''lám''; Welsh ''llaw'', Cornish ''leuv'', Old Breton ''lom'')

*''i''-stems

E.g. *''sūlis'' 'sight, view, eye' (feminine) ( Brittonic ''sulis'' ~ Old Irish ''súil'')

E.g. *''mori'' 'body of water, sea' (neuter) (Gaulish ''Mori''- ~ Old Irish ''muir'' ~ Welsh ''môr'')

*''u''-stem nouns

E.g. *''bitus'' 'world, existence' (masculine) (Gaulish ''Bitu''- ~ Old Irish ''bith'' ~ Welsh ''byd'' ~ Breton ''bed'')

E.g. " rotisserie spit" (neuter)

Velar and dental stems

Before the ''*-s'' of the nominative singular, a velar consonant was fricated to ''*-x'' : "king" > . Likewise, final ''*-d'' devoiced to ''*-t-'': "druid" > .

E.g. "king" (masculine)

E.g. "druid" (masculine)

E.g. "friend" (masculine)

Nasal stems

Generally, nasal stems end in *-''on''-; this becomes *-''ū'' in the nominative singular: *''abon-'' "river" > *''abū.''

E.g. "river" (feminine)

E.g. "name" (neuter)

*''s''-stem nouns

Generally,-stems contain an ''*-es-'', which becomes ''*-os'' in the nominative singular: 'house' > .

E.g. "house" (neuter)

*''r''-stem nouns

*''r''-stems are rare and principally confined to names of relatives. Typically they end in *-''ter''-, which becomes *-''tīr'' in the nominative and *-''tr''- in all other cases aside from the accusative: *''ɸater''- 'father' > *''ɸatīr'', *''ɸatros''.

E.g. *''ɸatīr'' 'father' (masculine)

E.g. *''mātīr'' 'mother' (feminine)

Pronouns

The following personal pronouns in Celtic can be reconstructed as follows:

The following third-person pronouns in Proto-Celtic may also be reconstructed.

Forms of the masculine singular relative pronoun *yo- can be found in the first Botorrita plaque: The form ''io-s'' in line 10 is the nominative singular masculine of the relative pronoun from Proto-Indo-European ''*yo-'' (Sanskrit ''ya-'', Greek ''hos''), which shows up in Old Irish only as the aspiration for leniting relative verb forms. Line 7 has the accusative singular ''io-m'' and the dative singular ''io-mui'' of the same root.

Adjectives

Adjectives in Proto-Celtic had positive, comparative, superlative and equative degrees of comparison.

Positive-degree inflection classes

Four inflection classes for positive-degree adjectives are known. Most adjectives belonged to the ''o-ā'' class, in which the adjectives inflected like masculine ''o''-stems, neuter ''o''-stems and feminine ''ā''-stems when agreeing with nouns of their respective genders. A much smaller minority of adjectives were ''i''- and ''u''-stems.

Consonant-stem adjectives also existed but were vanishingly rare, with only relics in Old Irish like "hot" < .

Comparative degree

The comparative degree was formed on most adjectives by attaching to the adjective stem. For instance, "old" would have a comparative "older". However, some Caland system adjectives instead had a comparative ending in , which was then extended to . For example, "wide" had a comparative .

Superlative degree

The superlative was formed by simply attaching to the adjective stem. In some adjectives where the stem ends in ''*s'', the suffix is truncated to by haplology. Thus, "old" would have a superlative "oldest" but (stem ) would have a superlative .

Verbs

From comparison between early Old Irish and Gaulish forms it seems that Continental and Insular Celtic verbs developed differently and so the study of Irish and Welsh may have unduly weighted past opinion of Proto-Celtic verb morphology. It can be inferred from Gaulish and Celtiberian as well as Insular Celtic that the Proto-Celtic verb had at least three moods:
* indicative — seen in e.g. 1st Gaulish ''delgu'' "I hold", Old Irish ''tongu'' "I swear"
* imperative — seen in e.g. 3rd Celtiberian ''usabituz'', Gaulish ''appisetu''
* subjunctive — seen in e.g. 3rd Gaulish ''buetid'' "may he be", Celtiberian ''asekati''
and four tenses:
* present — seen in e.g. Gaulish ''uediíu-mi'' "I pray", Celtiberian ''zizonti'' "they sow"
* preterite — seen in e.g. 3rd Gaulish ''sioxti'', Lepontic ''KariTe''
* imperfect — perhaps in Celtiberian ''kombalkez'', ''atibion''
* future — seen in e.g. 3rd Gaulish ''bissiet'', Old Irish ''bieid'' "he shall be"
A probable optative mood also features in Gaulish (''tixsintor'') and an infinitive (with a characteristic ending ''-unei'') in Celtiberian.

Verbs were formed by adding suffixes to a verbal stem. The stem might be thematic or athematic, an open or a closed syllable.

Primary endings

The primary endings in Proto-Celtic were as follows. They were used to form the present, future, and subjunctive conjugations.

Present-stem formations

Proto-Celtic possessed a diverse set of ways to form present stems. They can be roughly be divided into two broad categories of athematic and thematic.
* Thematic verbs feature a connecting vowel between the present stem and the basic primary endings. This vowel is ''-o-'' in the first-person and third-person plural and ''-e-'' in the third-person singular and second-person forms. The first-person singular of these verbs end in .
* Athematic verbs feature no such connecting vowel, and their 1st-person singular forms end in instead of .

These two inflectional categories can themselves be subdivided based on the means of derivation from a verb root via a combination of root ablaut grades and suffixes. These derivational classes include:

Nasal-infix presents

In Proto-Celtic, the Indo-European nasal infix presents split into two categories: ones originally derived from laryngeal-final roots (i.e. ''seṭ'' roots in Sanskrit), and ones that were not (i.e. from ''aniṭ'' roots). In ''seṭ'' verbs, the nasal appears at the end of the present stem, while in ''aniṭ''-derived verbs the nasal was followed by a root-final stop (generally ''-g-'' in Old Irish).

=To ''aniṭ'' roots

=
''Aniṭ'' nasal infix verbs conjugated exactly like basic thematic verbs in the present tense.

However, the origin of the invariant root vowel in ''-o-'' in ''*CewC-'' roots in Old Irish is unclear. Usually, it is held that the consonantism in these verbs was generalized in favour of the plural stem ''*CunC-'' in Old Irish. One would expect alternation between ''o'' in the 1st- and 3rd- person plural and ''-u-'' elsewhere in the present; but for both contexts Old Irish only attests ''-o-''.

The following verbs can be reconstructed in this class:
* To ''*CeyC-'' roots: , , ,
* Double-nasal presents: , ,
* To ''*CewC-'' roots: , , , , , , , ,
* Others: ,

=To ''seṭ'' roots

=
On the other hand, the ''seṭ'' presents originally had a long vowel after the nasal in the singular and ''-a-'' after the nasal in the plural, but the attested Celtic languages levelled this alternation away. Gaulish shows traces of the singular long-vowel vocalism while Old Irish generalized the plural ''-a-'' to the singular.

The ''seṭ'' nasal-infix presents were further subdivided into subcategories based on the root-final laryngeal. Traditionally two subclasses have long been accepted, the subclass (cited with a ''-ni-'' suffix) and (cited with a ''-na-'' suffix). nasal-infixed verbs were often leveled to act like verbs, being also cited with a ''-na-'' suffix; the only original difference between the two would have been the 3rd-person plural ending in ''*-nonti'' instead of ''*-nanti''.

The nasal-infix ''seṭ'' verbs in Proto-Celtic underwent multiple levelings. First, the suffixal vowel in the plural forms was harmonized so that they would all be the short counterpart to the vowel in the singular forms. Then all the long vowels in the singular were shortened to make the suffix vowel identical in quality and length across all person-number combinations.

The following ''seṭ''-root nasal presents are reconstructible for Proto-Celtic:
* ''*h₁''-final roots:
** ''-ni-'' relics: , ,
** Converted to ''-na-'' before Old Irish: , ,
* ''*h₂'' subclass: , , , (?), , , , ,
* ''*h₃''-final roots: , ,
* Semivowel-final aniṭ root: ,
* Unknown laryngeal: , , ,

Preterite formations

There were two or three major preterite formations in Proto-Celtic, plus another moribund type.
* The s-preterite
* The reduplicated suffixless preterite (originating from the PIE reduplicated stative)
* The t-preterite
* The root aorist

The s-, t-, and root aorist preterites take Indo-European secondary endings, while the reduplicated suffix preterite took stative endings. These endings are:

=t-preterite

=
The Old Irish t-preterite was traditionally assumed to be a divergent evolution from the s-preterite, but that derivation was challenged by Jay Jasanoff, who alleges that they were instead imperfects of Narten presents. Either derivation requires Narten ablaut anyway, leading to a stem vowel ''i'' in the singular and ''e'' in the plural. The stem vowel in the t-preterite was leveled to ''*e'' if the next consonant was either velar or ''*m'', and ''*i'' in front of ''*r'' or ''*l''.

=Suffixless preterites

=
Many suffixless preterite formations featured reduplication. The nature of the reduplication depends on the structure of the root.

Future formations

One major formation of the future in Celtic, the ''s''-future. It is a descendant of the Proto-Indo-European ''(h₁)se''- desiderative, with ''i''-reduplication in many verbs. The Old Irish ''a''- and ''s''-future come from here.

Another future formation, attested only in Gaulish, is the ''-sye-''desiderative.

Subjunctive formations

Most verbs took one subjunctive suffix in Proto-Celtic, ''-(a)s-'', followed by the thematic primary endings. It was a descendant of the subjunctive of an Indo-European sigmatic thematic formation '' *-seti''. The ''-ase-'' variant originated in roots that ended in a laryngeal in Proto-Indo-European; when the ''*-se-'' suffix was attached right after a laryngeal, the laryngeal regularly vocalized into ''*-a-''. It would then analogically spread to other Celtic strong verb roots ending in sonorants in addition to the weak verbs, even if the root did not originally end in a laryngeal.

There were also two, possibly three verbs that did not use ''-(a)se-'', instead straight-out taking thematised primary endings. They are: "to be, exist" (subjunctive ), "to hear" (subjunctive ), and possibly ''*ɸalnati'' “to approach, drive” (subjunctive ''*ɸeleti'').

Primary subjunctive formations in Proto-Celtic generally use the ''e''-grade of the verb root, even if the present stem uses the zero-grade.

Imperative formation

Imperative endings in Proto-Celtic were as follows:

=Second-person singular imperative

=
The second-person singular imperative was generally endingless in the active; no ending was generally added to athematic verbs. On thematic ''-e/o-'' verbs, the imperative ended in thematic vowel ''*-e''. However, there is also another second-person singular active imperative ending, ''-si'', which was attached to the verb root athematically even with thematic strong verbs.

The thematic deponent second-person singular imperative ending was ''*-eso''. The ''-the'' in Old Irish is secondary.

=Third-person imperative

=
The third-person imperative endings in Insular Celtic, Gaulish and Celtiberian have completely separate origins from each other. The Insular Celtic endings are derived from , Gaulish endings from , and the Celtiberian third-person imperative singular ending stems from .

Example conjugations

Scholarly reconstructions may be summarised in tabular format.

Copula

The copula ''*esti'' was irregular. It had both athematic and thematic conjugations in the present tense. Schrijver supposes that its athematic present was used clause-initially and the thematic conjugation was used when that was not the case.

Numerals

Vocabulary

The vast majority of reliably reconstructible lexical items in Proto-Celtic have good Indo-European etymologies, unlike what is found in, for example, the Greek language—at least 90% according to Matasovic. These include most of the items on the Swadesh list of basic vocabulary. But a few words that do not have Indo-European cognates, so may be borrowings from substrate or adstrate Pre-Indo-European languages, are also from basic vocabulary, including ''*bodyo-'' ‘yellow’ (though this has possible cognates in Italic), ''*kani'' "good," and ''*klukka'' "stone." It is notable that fully 32 items have been reconstructed for Proto-Celtic with the meaning "fight."English to Proto-Celtic Wordlist p. 44-45 https://www.wales.ac.uk/Resources/Documents/Research/CelticLanguages/EnglishProtoCelticWordList.pdf

Examples of morphology derivation from PIE

Two examples of verbs

(The following examples lack the dual plural and are conjugated in the present tense)

Examples of noun declension

(The following examples lack the dual number)

Masculine noun

Feminine noun

Neuter noun

An example of adjectival declension

(The following example lacks the dual number)

Derivation of personal pronouns (nominative case) from PIE

See also

* Pre-Celtic
* Italo-Celtic
* Beaker culture
* Urnfield
* Hallstatt culture
*La Tène culture
* Goidelic substrate hypothesis
* Ligures
* Azilian

References

Notes

Bibliography
*
*
*
*
*
*
*
*
*
*
*
*
*

External links

* Leiden University has compile
etymological dictionaries of various IE languages
a project supervised by Alexander Lubotsky.

{{DEFAULTSORT:Proto-Celtic Language
Celtic languages
Celtic