Proto-Celtic language explained

Proto-Celtic
Also Known As:	PC, Common Celtic
Region:	Central or Western Europe
Era:	ca. 1300–800 BC
Familycolor:	Indo-European
Ancestor:	Proto-Indo-European
Target:	Celtic languages

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^[1] and Middle Welsh,^[2] 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.^[3] 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 BCE to 1st century BCE); otherwise, descendant languages would have developed their own, unrelated words for their metal. However, Schumacher^[4] and Schrijver^[5] 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-).^[6]
- 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.^[7]
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.^[8]

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 > 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):^[9]
- 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

PIE	PC	Example
PIE	PC	PIE	Proto-Celtic		Old Irish		Welsh
				father	athir		edrydd	cf. home (< *ɸatrijo-)
				three	trí		tri
				sing hundred	canaid cét pronounced as //kʲeːd//		canu cant
				four	ceth(a)ir		pedwar
				apple	uball		afal
				see	derc	eye	drych	sight
				to glue jaw	glen(a)id giun, gin	(he) sticks fast mouth	glynu gên	adhere jaw
				woman	ben		O.W. ben
				carry	berid	(he) carries	adfer cymeryd^[10]	to restore to take
				suck	denait	they suck	dynu, denu
				take sickness	ga(i)bid galar	(he) takes sickness	gafael galar	hold grief
				kill, wound	gonaid	(he) wounds, slays	gwanu	stab
				old	sen		hen
				mother	máthir		modryb	cf. aunt
				nephew	niad		nai
				lick	ligid	(he) licks	llyo, llyfu
				king	rí (gen. ríg)		rhi
				young	óac		ieuanc
				rulership	flaith		gwlad	country

PIE	PC	Example
PIE	PC	PC		Old Irish		Welsh
				acc. *abonen	river	aub		afon
					brother	bráthir		brawd
					old	sen		hen
	between consonants^[11]				father	athir		edrydd	cf. home
					true	fír		gwir
					wheel	roth		rhod
	in final syllable				nephew	niæ		nai
	elsewhere				gift	dán		dawn
					world	bith		byd
					number	rím		rhif
					blind age	cáech —	one-eyed —	coeg hoedl	empty, one-eyed age
					god	día		duw
					one	óen oín; áen aín		un
	before			> *	young	óac		ieuanc
	elsewhere				stream	sruth		ffrwd
					mystery	rún		rhin
					silent	táue	silence (*)	taw
					people cow	túath bó		tud M.W. bu, biw
	before stops				wide	lethan		llydan
	before other consonants				rooster	cailech (Ogham gen. )		ceiliog
	before stops				act of bearing; mind	breth, brith		bryd
	before other consonants				dead	marb		marw
					subdue	M.Ir. damnaid	he ties, fastens, binds	—
					tooth	dét pronounced as //dʲeːd//		dant
	before obstruents				lordship	flaith		gwlad	country
	before sonorants				hand	lám		llaw
	before obstruents				betrayal	mrath		brad
	before sonorants				grain	grán		grawn
	(presumably with same distribution as above)				to tame	daimid fodam-	daimid -	goddef	endure, suffer
	(presumably with same distribution as above)		?		known	gnáth		gnawd	customary

Phonological reconstruction

Consonants

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

Manner	Voicing	Bilabial	Alveolar	Palatal	Velar
Manner	Voicing	Bilabial	Alveolar	Palatal		plain	labialized
Plosive	voiceless		pronounced as /t/		pronounced as /k/	pronounced as /kʷ/
Plosive	voiced	pronounced as /b/	pronounced as /d/		pronounced as /ɡ/	pronounced as /ɡʷ/
Fricative		pronounced as /ɸ/	pronounced as /s/		pronounced as /x/
Nasal			pronounced as /m/		pronounced as /n/
Approximant			pronounced as /l/	pronounced as /j/		pronounced as /w/
Trill			pronounced as /r/

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 [tʰ kʰ]. And unaspirated voiced stops /b d ɡ/ were devoiced to [p t k] word-initially.^[12] ^[13]

This allophony may be reconstructed to PC from the following evidence:^[12] ^[13]

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 [t]. This implies that Celtiberian /d/ had a voiceless allophone pronounced as /[t]/.

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 *[pʰ])^[12] 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.)

Proto-Celtic	Old Irish	Welsh
> * 'shine'	las-aid	llach-ar
> * 'seven'	secht	saith
or * 'heel'	seir	ffêr

In Gaulish and the Brittonic languages, the Proto-Indo-European * phoneme becomes a new * sound. Thus, Gaulish petuar[ios], Welsh pedwar "four", but Old Irish cethair and Latin quattuor. Insofar as this new pronounced as //p// 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 Ireland,http://www.sciencemag.org/cgi/content/full/288/5469/1158, 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 pronounced as //p// in loan words, though in early borrowings from Welsh into Primitive Irish, pronounced as //kʷ// was used by sound substitution due to a lack of a pronounced as //p// 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:

Type	Front		Central		Back
Type	long	short	long	short	long	short
Close	pronounced as /iː/	pronounced as /i/			pronounced as /uː/	pronounced as /u/
Mid	pronounced as /eː/	pronounced as /e/				pronounced as /o/
Open			pronounced as /aː/	pronounced as /a/

The following diphthongs have also been reconstructed:

+	Type	With -i	With -u
With a-	pronounced as /ai/	pronounced as /au/
With o-	pronounced as /oi/	pronounced as /ou/

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:^[14] 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)

Case	Singular	Dual	Plural
Nominative	makkʷos	makkʷou	makkʷoi
Vocative	makkʷe	makkʷou	makkʷūs
Accusative	makkʷom	makkʷou	makkʷūs
Genitive	makkʷī	makkʷūs	makkʷom
Dative	makkʷūi	makkʷobom	makkʷobos
Ablative	makkʷū	makkʷobim	makkʷobis
Instrumental	makkʷū	makkʷobim	makkʷūs
Locative	makkʷei	makkʷou	makkʷobis

However, Celtiberian shows -o- stem genitives ending in -o rather than -ī: aualo "[son] of Avalos".^[15]

dūnom 'stronghold' (neuter)

Case	Singular	Dual	Plural
Nominative	dūnom	dūnou	dūnā
Vocative	dūnom	dūnou	dūnā
Accusative	dūnom	dūnou	dūnā
Genitive	dūnī	dūnūs	dūnom
Dative	dūnūi	dūnobom	dūnobos
Ablative	dūnū	dūnobim	dūnobis
Instrumental	dūnū	dūnobim	dūnūs
Locative	dūnei	dūnou	dūnobis

ā-stem nouns

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

Case	Singular	Dual	Plural
Nominative	ɸlāmā	ɸlāmai	ɸlāmās
Vocative	ɸlāmā	ɸlāmai	ɸlāmās
Accusative	ɸlāmām	ɸlāmai	ɸlāmās
Genitive	ɸlāmās	ɸlāmajous	ɸlāmom
Dative	ɸlāmāi	ɸlāmābom	ɸlāmābos
Ablative	ɸlāmī	ɸlāmābim	ɸlāmābis
Instrumental	ɸlāmī	ɸlāmābim	ɸlāmābis
Locative	ɸlāmāi	ɸlāmābim	ɸlāmābis

i-stems

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

Case	Singular	Dual	Plural
Nominative	sūlis	sūlī	sūlīs
Vocative	sūli	sūlī	sūlīs
Accusative	sūlim	sūlī	sūlīs
Genitive	sūleis	sūljous	sūljom
Dative	sūlei	sūlibom	sūlibos
Ablative	sūlī	sūlibim	sūlibis
Instrumental	sūlī	sūlibim	sūlibis
Locative	sūlī	sūlibim	sūlibis

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

Case	Singular	Dual	Plural
Nominative	mori	morī	moryā
Vocative	mori	morī	moryā
Accusative	mori	morī	moryā
Genitive	moreis	moryous	moryom
Dative	morei	moribom	moribos
Ablative	morī	moribim	moribis
Instrumental	morī	moribim	moribis
Locative	morī	moribim	moribis

u-stem nouns

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

Case	Singular	Dual	Plural
Nominative	bitus	bitou	bitowes
Vocative	bitu	bitou	bitowes
Accusative	bitum	bitou	bitūs
Genitive	bitous	bitowou	bitowom
Dative	bitou	bitubom	bitubos
Ablative	bitū	bitubim	bitubis
Instrumental	bitū	bitubim	bitubis
Locative	bitū	bitubim	bitubis

E.g. Celtic languages: *beru "rotisserie spit" (neuter)

Case	Singular	Dual	Plural
Nominative	Celtic languages: *beru	Celtic languages: *berou	Celtic languages: *berwā
Vocative	Celtic languages: *beru	Celtic languages: *berou	Celtic languages: *berwā
Accusative	Celtic languages: *beru	Celtic languages: *berou	Celtic languages: *berwā
Genitive	Celtic languages: *berous	Celtic languages: *berowou	Celtic languages: *berowom
Dative	Celtic languages: *berou	Celtic languages: *berubom	Celtic languages: *berubos
Ablative	Celtic languages: *berū	Celtic languages: *berubim	Celtic languages: *berubis
Instrumental	Celtic languages: *berū	Celtic languages: *berubim	Celtic languages: *berubis
Locative	Celtic languages: *berū	Celtic languages: *berubim	Celtic languages: *berubis

Velar and dental stems

Before the *-s of the nominative singular, a velar consonant was fricated to *-x : Celtic languages: *rīg- "king" > Celtic languages: *rīxs. Likewise, final *-d devoiced to *-t-: Celtic languages: *druwid- "druid" > Celtic languages: *druwits.^[16]

E.g. "king" (masculine)

Case	Singular	Dual	Plural
Nominative	Celtic languages: *rīxs	Celtic languages: *rīge	Celtic languages: *rīges
Vocative	Celtic languages: *rīxs	Celtic languages: *rīge	Celtic languages: *rīges
Accusative	Celtic languages: *rīgam	Celtic languages: *rīge	Celtic languages: *rīgās
Genitive	Celtic languages: *rīgos	Celtic languages: *rīgou	Celtic languages: *rīgom
Dative	Celtic languages: *rīgei	Celtic languages: *rīgobom	Celtic languages: *rīgobos
Ablative	Celtic languages: *rīgī	Celtic languages: *rīgobim	Celtic languages: *rīgobis
Instrumental	Celtic languages: *rīge	Celtic languages: *rīgobim	Celtic languages: *rīgobis
Locative	Celtic languages: *rīgi	Celtic languages: *rīgobim	Celtic languages: *rīgobis

E.g. "druid" (masculine)

Case	Singular	Dual	Plural
Nominative	Celtic languages: *druwits	Celtic languages: *druwide	Celtic languages: *druwides
Vocative	Celtic languages: *druwits	Celtic languages: *druwide	Celtic languages: *druwides
Accusative	Celtic languages: *druwidem	Celtic languages: *druwide	Celtic languages: *druwidās
Genitive	Celtic languages: *druwidos	Celtic languages: *druwidou	Celtic languages: *druwidom
Dative	Celtic languages: *druwidei	Celtic languages: *druwidobom	Celtic languages: *druwidobos
Ablative	Celtic languages: *druwidī	Celtic languages: *druwidobim	Celtic languages: *druwidobis
Instrumental	Celtic languages: *druwide	Celtic languages: *druwidobim	Celtic languages: *druwidobis
Locative	Celtic languages: *druwidi	Celtic languages: *druwidobim	Celtic languages: *druwidobis

E.g. "friend" (masculine)

Case	Singular	Dual	Plural
Nominative	Celtic languages: *karants	Celtic languages: *karante	Celtic languages: *karantes
Vocative	Celtic languages: *karants	Celtic languages: *karante	Celtic languages: *karantes
Accusative	Celtic languages: *karantam	Celtic languages: *karante	Celtic languages: *karantās
Genitive	Celtic languages: *karantos	Celtic languages: *karantou	Celtic languages: *karantom
Dative	Celtic languages: *karantei	Celtic languages: *karantobom	Celtic languages: *karantobos
Ablative	Celtic languages: *karantī	Celtic languages: *karantobim	Celtic languages: *karantobis
Instrumental	Celtic languages: *karante	Celtic languages: *karantobim	Celtic languages: *karantobis
Locative	Celtic languages: *karanti	Celtic languages: *karantobim	Celtic languages: *karantobis

Nasal stems

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

E.g. "river" (feminine)

Case	Singular	Dual	Plural
Nominative	Celtic languages: *abū	Celtic languages: *abone	Celtic languages: *abones
Vocative	Celtic languages: *abū	Celtic languages: *abone	Celtic languages: *abones
Accusative	Celtic languages: *abonam	Celtic languages: *abone	Celtic languages: *abonās
Genitive	Celtic languages: *abonos	Celtic languages: *abonou	Celtic languages: *abonom
Dative	Celtic languages: *abonei	Celtic languages: *abnobom	Celtic languages: *abnobos
Ablative	Celtic languages: *abonī	Celtic languages: *abnobim	Celtic languages: *abnobis
Instrumental	Celtic languages: *abone	Celtic languages: *abnobim	Celtic languages: *abnobis
Locative	Celtic languages: *aboni	Celtic languages: *abnobim	Celtic languages: *abnobis

E.g. "name" (neuter)

Case	Singular	Dual	Plural
Nominative	Celtic languages: *anman	Celtic languages: *anmanī	Celtic languages: *anmanā
Vocative	Celtic languages: *anman	Celtic languages: *anmanī	Celtic languages: *anmanā
Accusative	Celtic languages: *anman	Celtic languages: *anmanī	Celtic languages: *anmanā
Genitive	Celtic languages: *anmēs	Celtic languages: *anmanou	Celtic languages: *anmanom
Dative	Celtic languages: *anmanei	Celtic languages: *anmambom	Celtic languages: *anmambos
Ablative	Celtic languages: *anmanī	Celtic languages: *anmambim	Celtic languages: *anmambis
Instrumental	Celtic languages: *anmane	Celtic languages: *anmambim	Celtic languages: *anmambis
Locative	Celtic languages: *anmani	Celtic languages: *anmambim	Celtic languages: *anmambis

s-stem nouns

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

E.g. "house" (neuter)

Case	Singular	Dual	Plural
Nominative	Celtic languages: *tegos	Celtic languages: *tegese	Celtic languages: *tegesa
Vocative	Celtic languages: *tegos	Celtic languages: *tegese	Celtic languages: *tegesa
Accusative	Celtic languages: *tegos	Celtic languages: *tegese	Celtic languages: *tegesa
Genitive	Celtic languages: *tegesos	Celtic languages: *tegesou	Celtic languages: *tegesom
Dative	Celtic languages: *tegesi	Celtic languages: *tegesobom	Celtic languages: *tegesobos
Ablative	Celtic languages: *tegesī	Celtic languages: *tegesobim	Celtic languages: *tegesobis
Instrumental	Celtic languages: *tegese	Celtic languages: *tegesobim	Celtic languages: *tegesobis
Locative	Celtic languages: *tegesi	Celtic languages: *tegesobim	Celtic languages: *tegesobis

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)

Case	Singular	Dual	Plural
Nominative	ɸatīr	ɸatere	ɸateres
Vocative	ɸatīr	ɸatere	ɸateres
Accusative	ɸateram	ɸatere	ɸaterās
Genitive	ɸatros	ɸatrou	ɸatrom
Dative	ɸatrei	ɸatrebom	ɸatrebos
Ablative	ɸatrī	ɸatrebim	ɸatrebis
Instrumental	ɸatre	ɸatrebim	ɸatrebis
Locative	ɸatri	ɸatrebim	ɸatrebis

E.g. *mātīr 'mother' (feminine)

Case	Singular	Dual	Plural
Nominative	mātīr	mātere	māteres
Vocative	mātīr	mātere	māteres
Accusative	māteram	mātere	māterās
Genitive	mātros	mātrou	mātrom
Dative	mātrei	mātrebom	mātrebos
Ablative	mātrī	mātrebim	mātrebis
Instrumental	mātre	mātrebim	mātrebis
Locative	mātri	mātrebim	mātrebis

Pronouns

The following personal pronouns in Celtic can be reconstructed as follows:^[17] ^[18]

Case	First-person		Second-person
Case	Singular	Plural	Singular	Plural
Nominative	Celtic languages: *mī	Celtic languages: *snī	Celtic languages: *tū	Celtic languages: *swī
Accusative	Celtic languages: *me^[19]	Celtic languages: *snos	Celtic languages: *tu	Celtic languages: *swes
Genitive	Celtic languages: *mene^[20]	?	Celtic languages: *towe	?

The following third-person pronouns in Proto-Celtic may also be reconstructed.^[21] ^[17]

Case	Singular			Plural
Case	Masculine	Feminine	Neuter	Plural
Nominative	Celtic languages: es, Celtic languages: ēs	Celtic languages: *sī	Celtic languages: *ed	Celtic languages: *eyes
Accusative	Celtic languages: *em	Celtic languages: seyam? Celtic languages: sīm?	Celtic languages: *ed	Celtic languages: *sūs
Genitive	Celtic languages: *esyo	Celtic languages: *esyās	Celtic languages: *esyo	Celtic languages: ēsom? Celtic languages: esom?
Dative Instrumental Locative	Celtic languages: *e(s)yōi	Celtic languages: *esyāi	Celtic languages: *e(s)yōi	Celtic languages: *ēbis

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.^[22]

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 Irish, Old (to 900);: té "hot" < Celtic languages: *teɸents.

Comparative degree

The comparative degree was formed on most adjectives by attaching Celtic languages: *-yūs to the adjective stem. For instance, Celtic languages: *senos "old" would have a comparative Celtic languages: *senyūs "older". However, some Caland system adjectives instead had a comparative ending in Celtic languages: *-is, which was then extended to Celtic languages: *-ais. For example, Celtic languages: *ɸlitanos "wide" had a comparative Celtic languages: *ɸletais.^[23]

Superlative degree

The superlative was formed by simply attaching Celtic languages: *-isamos to the adjective stem. In some adjectives where the stem ends in *s, the suffix is truncated to Celtic languages: *-(s)amos by haplology.^[23] Thus, Celtic languages: *senos "old" would have a superlative Celtic languages: *senisamos "oldest" but Celtic languages: *trexsnos (stem Celtic languages: *trexs-) would have a superlative Celtic languages: *trexsamos.

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.^[24] ^[25]

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.^[17]

Proto-Celtic primary endings
Person and number	Basic endings		Thematic present
Person and number	Active	Mediopassive	Active	Mediopassive
1st	Celtic languages: -ū (thematic) Celtic languages: -mi* (athematic)	Celtic languages: *-ūr	Celtic languages: *-ū	Celtic languages: *-ūr
2nd	Celtic languages: *-si	Celtic languages: *-tar	Celtic languages: *-esi	Celtic languages: *-etar
3rd	Celtic languages: *-ti	Celtic languages: *-tor	Celtic languages: *-eti	Celtic languages: *-etor
1st	Celtic languages: *-mosi	Celtic languages: *-mor	Celtic languages: *-omosi	Celtic languages: *-omor
2nd	Celtic languages: *-tesi	Celtic languages: *-dwe	Celtic languages: *-etesi	Celtic languages: *-edwe
3rd	Celtic languages: *-nti	Celtic languages: *-ntor	Celtic languages: *-onti	Celtic languages: *-ontor

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 Celtic languages: *-ū.
Athematic verbs feature no such connecting vowel, and their 1st-person singular forms end in Celtic languages: *-mi instead of Celtic languages: *-ū.

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:

Derivational classes of Proto-Celtic verbs! Inflectional class! Root ablaut! Affix! Class! KPV designation
Thematic	e-grade	(none)	Simple thematic	A-1
		-ye-	e-grade *-ye-	A-5
		-de-	e-grade *-de-	A-6
	o-grade	Celtic languages: -ī- Celtic languages: -eyo-	-eye- causative/iterative	(none)
	zero grade	(none)	Thematized root athematic	A-2
		(none)	tudáti-type thematic	A-2
		-ske-	-ske- inchoative	A-3
		-ye-	zero-grade *-ye-	A-4
		Nasal infix	Aniṭ-root nasal-infix	A-8
		i-reduplication	i-reduplicated present	A-15
	(varied)	-āye-	Denominative	(none)
Athematic	e-grade	(none)	CeRH-root present	A-13
	zero grade	-na- (when levelled)	seṭ-root nasal-infix	A-8
		-nu-	-new- present	A-10
		-ī-	essive	A-7
	(varied)	-ā-	factitive	(none)

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.^[26]

The seṭ nasal-infix presents were further subdivided into subcategories based on the root-final laryngeal. Traditionally two subclasses have long been accepted, the Indo-European languages: *h₁ subclass (cited with a -ni- suffix) and Indo-European languages: *h₂ (cited with a -na- suffix). Indo-European languages: *h₃ nasal-infixed verbs were often leveled to act like Indo-European languages: *h₂ 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.

Evolution of Proto-Celtic ablaut in the nasal infix for *seṭ* roots
Person and number	Pre-leveling			Leveling of vowel quality		Leveling of vowel length
Person and number	Indo-European languages: *h₁ verbs	Indo-European languages: *h₂ verbs	Indo-European languages: *h₃ verbs	Indo-European languages: *h₁ verbs	Indo-European languages: h₂ and Indo-European languages: h₃ verbs	Indo-European languages: *h₁ verbs	Indo-European languages: h₂ and Indo-European languages: h₃ verbs
1st	Celtic languages: *-nīmi	Celtic languages: *-nāmi	Celtic languages: *-nāmi	Celtic languages: *-nīmi	Celtic languages: *-nāmi	Celtic languages: *-nimi	Celtic languages: *-nami
2nd	Celtic languages: *-nīsi	Celtic languages: *-nāsi	Celtic languages: *-nāsi	Celtic languages: *-nīsi	Celtic languages: *-nāsi	Celtic languages: *-nisi	Celtic languages: *-nasi
3rd	Celtic languages: *-nīti	Celtic languages: *-nāti	Celtic languages: *-nāti	Celtic languages: *-nīti	Celtic languages: *-nāti	Celtic languages: *-niti	Celtic languages: *-nati
1st	Celtic languages: *-namosi	Celtic languages: *-namosi	Celtic languages: *-namosi	Celtic languages: *-nimosi	Celtic languages: *-namosi	Celtic languages: *-nimosi	Celtic languages: *-namosi
2nd	Celtic languages: *-natesi	Celtic languages: *-natesi	Celtic languages: *-natesi	Celtic languages: *-nitesi	Celtic languages: *-natesi	Celtic languages: *-nitesi	Celtic languages: *-natesi
3rd	Celtic languages: *-nenti	Celtic languages: *-nanti	Celtic languages: *-nonti	Celtic languages: *-ninti	Celtic languages: *-nanti	Celtic languages: *-ninti	Celtic languages: *-nanti

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:^[27]

Proto-Celtic preterite endings
Person and number	Ending type
Person and number	Secondary endings	Stative endings
1st	Celtic languages: *-am	Celtic languages: *-a
2nd	Celtic languages: *-s	Celtic languages: *-as
3rd	Celtic languages: *-t	Celtic languages: *-e
1st	Celtic languages: *-mo(s)	Celtic languages: *-mo
2nd	Celtic languages: *-te(s)	Celtic languages: *-te
3rd	Celtic languages: *-ant	Celtic languages: *-ar

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.^[28]

Suffixless preterites

Many suffixless preterite formations featured reduplication. The nature of the reduplication depends on the structure of the root.^[27]

Proto-Celtic suffixless preterites
Root	Meaning	Shape	Preterite stem	Notes
Celtic languages: *keng-	"to step"	Other root types	Celtic languages: *ke-kong-	Classic Indo-European reduplication, where the root is put in the o-grade and the prefixed reduplicant is formed with the first consonant followed by *e.
Celtic languages: *nigʷ-	"to wash"	C(R)eiT-	Celtic languages: *ni-noig-	In Proto-Celtic, roots with a semivowel (PIE Indo-European languages: -y- or -w-) before a non-laryngeal consonant have the reduplicant formed not with the first consonant of the root followed by *e, but instead the first consonant of the root followed by the semivowel. The root itself remains in the o-grade.
Celtic languages: *duk-	"to lead, carry"	C(R)euT-	Celtic languages: *du-douk-
Celtic languages: *gʷed-	"to pray"	CeT-	Celtic languages: *gʷād-	Roots ending in only a single stop as their coda generally merely change the stem vowel to Celtic languages: ā to form their preterite, without apparent reduplication. It originally spread from Celtic languages: ād-* (from Indo-European languages: h₁e-h₁od-), the preterite stem for Celtic languages: *ed- "to eat".
Celtic languages: *kerd-	"to throw, put"	CeRT-	Celtic languages: *kard-	A few roots in CeRT- also had the CeT- preterite formation applied to them but the long Celtic languages: *ā was shortened due to Osthoff's law.
Celtic languages: *dā-	"to give"	C(C)eH-	Celtic languages: de-dū (singular) Celtic languages: ded(a)- (plural)	Laryngeal-final roots produced long vowels in the root syllable in the singular, but not in the plural (where the root was in the zero-grade instead). Usually the singular stem was generalized in Celtic, but in these cases the plural stem was generalized.
Celtic languages: *kʷri-	"to buy"	C(R)eiH-	Celtic languages: *kʷi-kʷr-	The treatment for CeH- roots was also extended to C(R)eiH- roots. Due to the roots' semivowel, the reduplicant also contains the semivowel.

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.^[29]

There were also three verbs that did not use -(a)se-, instead straight-out taking thematised primary endings. Two of these verbs are Celtic languages: *bwiyeti "to be, exist" (subjunctive Celtic languages: *bweti) and Celtic languages: *klinutor "to hear" (subjunctive Celtic languages: *klowetor).^[30]

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:^[17] ^[31]

Imperative endings in Proto-Celtic
Person and number	Active endings
Person and number	Basic endings	With thematic vowels
2nd	-∅, Celtic languages: *-si	Celtic languages: *-e
3rd	Celtic languages: -tou, Celtic languages: -tūd, Celtic languages: *-tu	Celtic languages: -etou, Celtic languages: -etūd, Celtic languages: *-etu
1st	Celtic languages: *-mo(s)	Celtic languages: *-omo(s)
2nd	Celtic languages: *-te(s)	Celtic languages: *-ete(s)
3rd	Celtic languages: -ntou, Celtic languages: -ntu	Celtic languages: -ontou, Celtic languages: -ontu

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.^[32]

The thematic deponent second-person singular imperative ending was *-eso. The -the in Old Irish is secondary.^[33] ^[17]

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 Celtic languages: *-tou, *-ntou, Gaulish endings from Celtic languages: *-tu, *-ntu, and the Celtiberian third-person imperative singular ending stems from Celtic languages: *-tūd.^[31]

Example conjugations

See also: Grammatical conjugation. Scholarly reconstructions ^[34] ^[35] ^[36] may be summarised in tabular format.

!rowspan="2"
							Medio- passive
Person	Present		Imperfect		Future		Past
Indicative	1st	berū	berūr	beremam	—	bibrāsū	bibrāsūr	bīram	—
	2nd	beresi	beretar	beretās	—	bibrāsesi	bibrāsetar	birs	—
	3rd	bereti	beretor	bereto	—	bibrāseti	bibrāsetor	birt	?
	1st	beromosi	beromor	beremo	—	bibrāsomosi	bibrāsomor	berme	—
	2nd	beretesi	beredwe	?	—	bibrāsete	bibrāsedwe	berte	—
	3rd	beronti	berontor	berento	—	bibrāsonti	bibrāsontor	berant	?
Subjunctive	1st	berasū	berasūr	—	—	—	—	—	—
	2nd	berasesi	berasetar	—	—	—	—	—	—
	3rd	beraseti	berasetor	—	—	—	—	—	—
	1st	berasomosi	berasomor	—	—	—	—	—	—
	2nd	berasetesi	berasedwe	—	—	—	—	—	—
	3rd	berasonti	berasontor	—	—	—	—	—	—
Imperative	2nd	bere	bereso	—	—	—	—	—	—
	3rd	beretou	?	—	—	—	—	—	—
	1st	beromos	?	—	—	—	—	—	—
	2nd	berete	?	—	—	—	—	—	—
	3rd	berontou	?	—	—	—	—	—	—
Participle		beronts	beromnos	—	—	—	—	bertyos	britos

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.^[37]

Conjugation of *esti in Proto-Celtic
Person	Present
Person	Athematic	Thematic
1st sg.	Celtic languages: *esmi	Celtic languages: *esū
2nd sg.	Celtic languages: *esi	Celtic languages: *esesi
3rd sg.	Celtic languages: *esti	Celtic languages: *eseti
1st pl.	Celtic languages: *esmosi	Celtic languages: *esomosi
2nd pl.	Celtic languages: {{asterisk	Celtic languages: *esetes
3rd pl.	Celtic languages: *senti	Celtic languages: {{asterisk

Numerals

!Numeral!PIE!PC
One (1)	h₁óynos	oinos
Two (2)	dwóh₁	duwo
Three (3)	tréyes	trīs
Four (4)	kʷetwóres	kʷetwores
Five (5)	pénkʷe	kʷenkʷe
Six (6)	swéḱs	swexs
Seven (7)	septḿ̥	seɸtam > *sextam
Eight (8)	oḱtṓw	oxtū
Nine (9)	h₁néwn̥	nowan
Ten (10)	déḱm̥	dekam

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.^[38] 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."^[39] It is notable that fully 32 items have been reconstructed for Proto-Celtic with the meaning "fight."^[40]

Examples of morphology derivation from PIE

Two examples of verbs

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

"To bear/carry"!Pronoun!PIE!PC
I	bʰéroh₂	berū
You	bʰéresi	beresi
He, she, it	bʰéreti	bereti
We	bʰéromos	beromosi
You (all)	bʰérete	beretesi
They	bʰéronti	beronti

"To be" (athematic version)!Pronoun!PIE!PC
I	h₁ésmi	esmi
You	h₁ési	esi
He, she, it	h₁ésti	esti
We	h₁smós	esmosi
You (all)	h₁sté	estes
They	h₁sénti	senti

Examples of noun declension

(The following examples lack the dual number)

Masculine noun

"Bear"!Case!Singular!Plural
Nom.	PIE h₂ŕ̥tḱos > PC artos	PIE h₂ŕ̥tḱoes* > PC *artoi
Gen.	h₂ŕ̥tḱosyo > *artī	h₂ŕ̥tḱoHom > *artom
Dat.	h₂ŕ̥tḱoey > *artūi	h₂ŕ̥tḱomos > *artobos
Acc.	h₂ŕ̥tḱom > *artom	h₂ŕ̥tḱoms > *artoms
Voc.	h₂ŕ̥tḱe > *arte	h₂ŕ̥tḱoes > *artūs
Loc.	h₂ŕ̥tḱey > *artei	h₂ŕ̥tḱoysu > ?
Instr.	h₂ŕ̥tḱoh₁ > *artū	h₂ŕ̥tḱōys > *artūis

Feminine noun

"Open land"!Case!Singular!Plural
Nom.	PIE ln̥dʰéh₂* > PC *landā	PIE ln̥dʰéh₂es* > PC *landās
Gen.	ln̥dʰéh₂s > *landās	ln̥dʰéh₂oHom > *landom
Dat.	ln̥dʰéh₂ey > *landāi	ln̥dʰéh₂mos > *landābos
Acc.	ln̥dʰā́m > *landam	ln̥dʰéh₂m̥s > *landāms
Voc.	ln̥dʰéh₂ > *landā	ln̥dʰéh₂es > *landās
Loc.	ln̥dʰéh₂i > *landai	ln̥dʰéh₂su > ?
Instr.	ln̥dʰéh₂h₁ > ?	ln̥dʰéh₂mis > *landābis

Neuter noun

"Yoke"!Case!Singular!Plural
Nom.	PIE yugóm > PC yugom	PIE yugéh₂ > PC yugā
Gen.	yugósyo > *yugī	yugóHom > *yugom
Dat.	yugóey > *yugūi	yugómos > *yugobos
Acc.	yugóm > *yugom	yugéh₂ > *yugā
Voc.	yugóm > *yugom	yugéh₂ > *yugā
Loc.	yugéy > *yugei	yugóysu > ?
Instr.	yugóh₁ > *yugū	yugṓys > *yugūis

An example of adjectival declension

(The following example lacks the dual number)

"High"!Case!Masculine(singular)!Feminine(singular)!Neuter(singular)
Nom.	PIE h₂ḱrós > PC akros	PIE h₂ḱréh₂ > PC akrā	PIE h₂ḱróm > PC akrom
Gen.	h₂ḱrósyo > *akrī	h₂ḱréh₂s > *akrās	h₂ḱrósyo > *akrī
Dat.	h₂ḱróey > *akrūi	h₂ḱréh₂ey > *akrai	h₂ḱróey > *akrūi
Acc.	h₂ḱróm > *akrom	h₂ḱrā́m > *akram	h₂ḱróm > *akrom
Voc.	h₂ḱré > *akre	h₂ḱréh₂ > *akrā	h₂ḱróm > *akrom
Instr.	h₂ḱróh₁ > *akrū	h₂ḱréh₂h₁ > ?	h₂ḱróh₁ > *akrū

!Case!Masculine(plural)!Feminine(plural)!Neuter(plural)
Nom.	PIE h₂ḱróes > PC akroi	PIE h₂ḱréh₂es > PC akrās	PIE h₂ḱréh₂ > PC akrā
Gen.	h₂ḱróHom > *akrom	h₂ḱréh₂oHom > *akrom	h₂ḱróHom > *akrom
Dat.	h₂ḱrómos > *akrobos	h₂ḱréh₂mos > *akrābos	h₂ḱrómos > *akrobis
Acc.	h₂ḱróms > *akroms	h₂ḱréh₂m̥s > *akrams	h₂ḱréh₂ > *akrā
Voc.	h₂ḱróes > *akroi	h₂ḱréh₂es > *akrās	h₂ḱréh₂ > *akrā
Instr.	h₂ḱrṓys > *akrobis	h₂ḱréh₂mis > *akrābis	h₂ḱrṓys > *akrobis

Derivation of personal pronouns (nominative case) from PIE

!Pronoun!PIE!PC
I	éǵ > me [acc.]*	mī
You	túh₂	tū
He	ís	se
She	só [m.] > séh₂ [f.]* > variant *sih₂	sī
It	íd	ed
We	wéy > nos [acc.] > variant* *nēs	snīs; *snīsnīs
You (all)	yū́ > wos [acc.]* > variant *wēs	swīs; *swīswīs
They	éyes	eyes

References

Notes

Bibliography

Book: Cowgill, Warren. Warren Cowgill. 1975. The origins of the Insular Celtic conjunct and absolute verbal endings. Flexion und Wortbildung: Akten der V. Fachtagung der Indogermanischen Gesellschaft, Regensburg, 9.–14. September 1973. H. Rix . 40–70. Wiesbaden. Reichert.
Book: Evans, D. Simon . A Grammar of Middle Welsh . . Dublin Institute for Advanced Studies . 1964 .
Hackstein, Olav . Uridg. *CH.CC > *C.CC . Historische Sprachforschung . 1–22 . 2002 . 115 .
Lane, George S. . The Germano-Celtic Vocabulary . Language . 9 . 3 . 244–264 . 1933 . 10.2307/409353 . 409353 .
Book: Matasović, Ranko. Etymological Dictionary of Proto-Celtic . . Brill Academic Publishers. 2009 . 978-90-04-17336-1.
Book: Matasović, Ranko. Addenda et corrigenda to Ranko Matasović's Etymological Dictionary of Proto-Celtic . . Brill Academic Publishers. 2011 .
Book: McCone, Kim . Towards a Relative Chronology of Ancient and Medieval Celtic Sound Change . . . 1996 . 978-0-901519-40-5 .
Book: Pedersen, Holger . Vergleichende Grammatik der keltischen Sprachen . 2. Band, Bedeutungslehre (Wortlehre). . Vandenhoeck & Ruprecht . 1913 . 978-3-525-26119-4.
Peter Schrijver (linguist) . Schrijver, Peter . The Celtic adverbs for 'against' and 'with' and the early apocope of *-i . Ériu . 1994 . 45 . 151–89.
Book: Schrijver, Peter . Peter Schrijver (linguist) . Studies in British Celtic Historical Phonology . . Rodopi . 1995 . 978-90-5183-820-6 .
Book: Schrijver, Peter. Proceedings of the XIV International Congress of Celtic Studies, Maynooth 2011. Pruners and trainers of the Celtic family tree: The rise and development of Celtic in light of language contact. 2015. Dublin. Dublin Institute for Advanced Studies. 191–219.
Book: Thurneysen, Rudolf . A Grammar of Old Irish . . Dublin . Dublin Institute for Advanced Studies . 1946 . Rudolf Thurneysen .
Book: Zair, Nicholas . The Reflexes of the Proto-Indo-European Laryngeals in Celtic . Leiden . Brill . 2012 .

External links

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

Notes and References

https://www.britannica.com/art/Celtic-literature#ref42288 Celtic literature
Rhys. John. Evans. E. Vincent. The Origin of the Welsh Englyn and Kindred Metres. Y Cymmrodor. 1905. XVIII. Honourable Society of Cymmrodorion. London.
Koch, John T. (2020). Celto-Germanic Later Prehistory and Post-Proto-Indo-European vocabulary in the North and West, pp. 45–48.
Book: Schumacher . Stefan . Die keltischen Primärverben. Ein vergleichendes, etymologisches und morphologisches Lexikon . 2004 . Institut für Sprachen und Literaturen der Universität Innsbruck . Innsbruck, Austria . 3-85124-692-6 . 85 . de.
Book: Schrijver . Peter . Peter Schrijver . Koch . John T. . Cunliffe . Barry . John T. Koch . Barry Cunliffe . Celtic from the West 3: Atlantic Europe in the Metal Ages – Questions of Shared Language . 2016 . . Oxford, UK . 978-1-78570-227-3 . 489–502 . 17. Ancillary study: Sound Change, the Italo-Celtic Linguistic Unity, and the Italian Homeland of Celtic . https://books.google.com/books?id=HP4sDwAAQBAJ&q=%22peter+schrijver%22+%22celtic+from+the+west+3%22&pg=PA9 . May 12, 2019 .
Matasovic, R. (2009) Etymological Dictionary of Proto-Celtic. Brill. p.7
Salmon, Joseph (1992) Accentual Change and Language Contact Stanford UP
Matasovic, R. (2009) Etymological Dictionary of Proto-Celtic. Brill. pp.11–12
Cólera, Carlos Jordán (2007) "Celtiberian," e-Keltoi: Journal of Interdisciplinary Celtic Studies: Vol. 6, Article 17. p.759. Available at: https://dc.uwm.edu/ekeltoi/vol6/iss1/17 accessed June 21, 2023
Welsh adfer 'to restore' < *ate-ber-, cymeryd < obsolete cymer < M.W. cymeraf < *kom-ber- (with -yd taken from the verbal noun cymryd < *kom-britu).
However, according to Hackstein (2002) *CH.CC > Ø in unstressed medial syllables. Thus, H can disappear in weak cases while being retained in strong cases, e.g. IE nom.sg. *dʰugh₂tḗr vs. gen.sg. *dʰugtr-os 'daughter' > early PC *dugater- ~ dugtr-. This then led to a paradigmatic split, resulting in Celtiberian gen.sg. tuateros, nom.pl. tuateres vs. Gaulish duxtir (< *dugtīr). (Zair 2012: 161, 163).
Eska . Joseph F. . Laryngeal Realism and the Prehistory of Celtic . Transactions of the Philological Society . Wiley . 116 . 3 . March 12, 2018 . 0079-1636 . 10.1111/1467-968x.12122 . 320–331.
Eska . Joseph . Laryngeal Realism and early Insular Celtic orthography . North American Journal of Celtic Studies . 3 . 1 . January 26, 2021 . 2472-7490 . 1–17 . November 24, 2021.
Book: Pedersen, Holger . Vergleichende Grammatik der keltischen Sprachen, 2. Band, Bedeutungslehre (Wortlehre) . Vandenhoeck & Ruprecht . Göttingen . 1913 . 978-3-525-26119-4 .
Untermann, J. (1967). "Die Endung des Genitiv singularis der o-Stämme im Keltiberischen." In W. Meid (ed.), Beiträge zur Indogermanistik und Keltologie, Julius Pokorny zum 80. Geburtstag gewidmet, pp. 281–288. Innsbruck: Sprachwissenschaftliches Institut der Universität Innsbruck.
Whitley. Stokes. Celtic Declension. Transactions of the Philological Society. 20. 1. 97–201. November 1887.
Book: McCone, Kim . The Origins and Development of the Insular Celtic Verbal Complex . Department of Old Irish, National University of Ireland . Maynooth studies in Celtic linguistics . 2006 . 978-0-901519-46-7.
Book: Thurneysen, Rudolf. Rudolf Thurneysen. Binchy. D. A. Osborn. Bergin. A Grammar of Old Irish. Dublin Institute for Advanced Studies. 1940. 1-85500-161-6.
Remade as Celtic languages: *mu in the prehistory of Irish by analogy to Celtic languages: *tu.
Remade as Celtic languages: *mowe in the prehistory of Irish by analogy to Celtic languages: *towe.
Book: Schrijver, Peter. Studies in the History of Celtic Pronouns and Particles . Department of Old Irish, National University of Ireland . Maynooth studies in Celtic linguistics . 1997 . 978-0-901519-59-7.
Matasovic, R. Etymological Dictionary of Proto-Celtic. Leiden: Brill. 2006. p. 436
The origin of the Celtic comparative type OIr. tressa, MW trech 'stronger'. 1991. Die Sprache. 34. 171–189. Jay. Jasanoff.
Stefan Schumacher, Die keltischen Primärverben: Ein vergleichendes, etymologisches und morphologisches Lexikon (Innsbruck: Institut für Sprachen und Literaturen der Universität, 2004).
Pierre-Yves Lambert, La langue gauloise: Description linguistique, commentaire d'inscriptions choisies (Paris: Errance, revised ed. 2003).
Lambert . Pierre-Yves . Stifter . David . Le plomb gaulois de Rezé . Études Celtiques . 38 . 1 . 2012 . 0373-1928 . 10.3406/ecelt.2012.2351 . 139–164 . fr, en.
Book: Schumacher. Stefan. Schulze-Thulin. Britta. aan de Wiel. Caroline. Die keltischen Primärverben. Ein vergleichendes, etymologisches und morphologisches Lexikon. 2004. Institut für Sprachen und Kulturen der Universität Innsbruck. Innsbruck. 3-85124-692-6. de.
Book: Jasanoff, Jay. Long-vowel preterites in Indo-European. Melchert. Craig. The Indo-European Verb. Wiesbaden . Reichert Verlag. 2012 . 127–135.
Book: McCone, Kim. The Indo-European Origins of the Old Irish Nasal Presents, Subjunctives and Futures . IBS-Vertrieb . Innsbrucker Beiträge zur Sprachwissenschaft . 1991 . 978-3-85124-617-9.
Darling . Mark . The Subjunctive in Celtic: Studies in Historical Phonology and Morphology . 2020 . University of Cambridge . 10.17863/CAM.57857 . September 1, 2022. Thesis .
Book: Stüber, Karin. The morphology of Celtic. Handbook of Comparative and Historical Indo-European Linguistics. 2. De Gruyter Mouton. Jared Klein. Brian Joseph. Matthias Fritz. 1203–1217.
Jasanoff . Jay. Old Irish tair 'come!' . Transactions of the Philological Society . Wiley . 84 . 1 . 1986 . 0079-1636 . 10.1111/j.1467-968x.1986.tb01050.x . 132–141.
Barnes . Timothy. Old Irish cuire, its congeners, and the ending of the 2nd sg. middle imperative . Ériu . 65 . 1 . 2015 . 2009-0056 . 49–56 . 10.3318/eriu.2015.65.3. September 2, 2022.
Alexander MacBain, 1911, xxxvi–xxxvii; An etymological dictionary of the Gaelic language; Stirling: Eneas MacKay
Alan Ward, A Checklist of Proto-Celtic Lexical Items (1982, revised 1996), 7–14.
Examples of attested Gaulish verbs at https://www.angelfire.com/me/ik/gaulish.html
Book: Schrijver, Peter. Dispersals and Diversification . Italo-Celtic and the Inflection of *es- ‘be’ . Brill. December 6, 2019 . 10.1163/9789004416192_012 . 209–235. 9789004414501 . 213806505 . Serangeli. Matilde. Olander. Thomas.
Matasovic, R. (2009)Etymological Dictionary of Proto-Celtic Leiden: Brill. p. 443
Matasovic, R. (2009)Etymological Dictionary of Proto-Celtic Leiden: Brill. p. 443-444
English to Proto-Celtic Wordlist p. 44-45 https://www.wales.ac.uk/Resources/Documents/Research/CelticLanguages/EnglishProtoCelticWordList.pdf