Wiktionary:About Proto-Brythonic

Proto-Brythonic is the last common ancestral stage of the Brythonic languages: Western Brythonic Welsh, Southwestern Brythonic Breton and Cornish, and likely Cumbric as well.

Phonology and notation edit

Consonants edit

  • Sonorants: *l, *ll, *r, *rr, *m, *n
  • Approximants: *j, *w
  • Voiceless plosives: *p, *t, *k
  • Voiced plosives: *b, *d, *g
  • Labialized voiced plosives: *gw
  • Voiceless fricatives: *f, *θ, *x, *h, *s
  • Labialized voiceless fricatives: *hw
  • Voiced fricatives: *β, *ð, *ɣ, *β̃

Vowels edit

  • Back rounded: *u, *o, *ọ
  • Central rounded: *ʉ
  • Front rounded: *ü, *ö
  • Central unrounded: *a, *ɨ
  • Front unrounded: *e, *ė, *i

/oɨ/ and /uɨ/ were the regular development of long /ɛː/ and /eː/, respectively, while also resulting from vocalization of certain consonants following /o/ and /u/, whence also developed /aɨ/ and (partially) /ei/.

Diphthongs edit


  • Front unrounded: *ėi, *ei
  • Front rounded: *üi, *öi
  • Central unrounded: *aɨ
  • Central rounded: *ʉɨ
  • Back rounded: *uɨ, *oɨ, *ọɨ

U-diphthongs (which we spell with w):

  • Front unrounded: *iw, *ɨw,*ėw, *ew
  • Front rounded: *üw, *öw
  • Central unrounded: *aw
  • Central rounded: *ʉw
  • Back rounded: *ow, *ọw

Developments from Proto-Celtic edit

Vowel development from Proto-Celtic to Late Brythonic:

Proto-Celtic Proto-Brythonic
Normally a-aff. final i-aff. intern. i-aff.
u u o ü ü
o o ü ö
i ɨ e
e e ɨ ė
a a ė ė
ū i
ī i
oi ʉ
ou ʉ

In closed pretonic and pre-pretonic syllables, short -u- and -i- had been been reduced to rounded and unrounded schwas, respectively.

Vowel affection edit

A-affection edit

When followed by the vowel /a/ in the final syllable, the short high vowels /i/ and /u/ are lowered to /e/ and /o/, respectively.

This leads to a masculine-feminine distinction in some o-stem adjectives, as the masculine form continues /i/, and the feminine form now has /e/.

Final i-affection edit

When short back or non-high front vowels in penultimate position are followed by front high vowels or semivowels, mainly /iː/ or /j/, they are subsequently fronted and (if possible) raised:

  • /e/ becomes /i/:

Short /e/ is also the only vowel that is affected by short /i/: Proto-Celtic *gʷeltis > Proto-Brythonic *gwɨlt

  • /a/ becomes raised /e̝/: Proto-Celtic *rīganī (queen) > Proto-Brythonic *rriɣėn
  • /o/ and /u/ become /y/: Proto-Celtic *ɸlowī > Proto-Brythonic *llüw

Internal i-affection edit

When short non-front-high vowels in any position are followed by front high vowels or semivowel /i/, /e̝/, /y/ or /j/, they are raised and/or fronted:

  • /e/ and /a/ become /e̝/:
  • /u/ becomes /y/:
  • /o/ becomes /ø/:

Miscellaneous raisings edit

/e/ and /o/ raised to /i/ and /u/ respectively before -rn-. o also raised to u before -rg-. /e/ also raised to /i/ before intervocalic -g-. These raisings may be reversed if a-affection is present.

Consonant mutation edit

Initial consonant mutation is essentially the same phenomenon as lenition, as well as other forms of consonant development, only now applied across word-boundaries. *esyo tegos > *esyo degoh (lenited); *esyās tegos > *esyāh tegoh > *esyāh θegoh (spirantized).

In the table below, the symbol ◌̞ is used to indicate a more weakly articulated version of a consonant, and ◌̬ to indicate a partially voiced version of a voiceless consonant; in both cases which the lenited consonant is derived from this version.

Radical Lenited Spirantized Nasalized
b β (< ) No change m
d ð (< ) n
ɡ ɣ (< ɡ˕) ŋ
p b (< ) f mh
t d (< ) θ nh
k ɡ (< ) x ŋh
m β̃ (< ) No change No change
ll l
rr r
s h (< )
st s(s)
ɡw ɣw ŋw

Development in the Brythonic languages edit

Basic vowel reflexes edit

Proto-Brythonic Breton Cornish Welsh
ʉ u u u
u o w, y
o o o o
eu eu, e aw, o1, 2
a a a a
e e e e
ė e, ei y e, ei, ai3, y
i i i, y i
ɨ e i y
ü y
oue o, oy wy
oe, oa, oua oe, oy oe
ae e ae
ei ei ey, y ai3, ei
üi ei ea wy


  • 1 In non-stressed Old Welsh syllables.
  • 2 Accent shift from ultima to penultima beyond Old Welsh caused monophthongization of ⟨aw⟩ to ⟨o⟩.
  • 3 ⟨ei⟩ becomes ⟨ai⟩ in Modern Welsh stressed monosyllables and final syllables.

Miscellaneous changes edit

The sequence *wo- led to *wa- in leniting positions, but was retained in non-leniting positions. This allomorphy was resolved separately in the daughter languages, with one reflex being generalized over the other.

Nouns edit

The plural is usually formed based on the Proto-Celtic nominative plural.

o-stem (masculine) Proto-Celtic Proto-Brythonic Welsh
Singular *bardos *barð bardd
Plural *bardoi *bėrð beirdd
o-stem (neuter) Proto-Celtic Proto-Brythonic Welsh
Singular *argantom *arɣant arian
Plural *argantā *arɣant *arian1
yo-stem Proto-Celtic Proto-Brythonic Welsh
Singular [Term?] [Term?] [Term?]
Plural [Term?] [Term?] [Term?]
ā-stem Proto-Celtic Proto-Brythonic Welsh
Singular *trebā *treβ tref
Plural *trebās *treβ *tref1
yā-stem Proto-Celtic Proto-Brythonic Welsh
Singular [Term?] [Term?] [Term?]
Plural [Term?] [Term?] [Term?]
ī/yā-stem Proto-Celtic Proto-Brythonic Welsh
Singular *rīganī *rriɣėn rhiain
Plural *rīgan(i)yās *rriɣaneð rhianedd
i-stem (animate) Proto-Celtic Proto-Brythonic Welsh
Singular *mrogis *broɣ bro
Plural *mrogīs *broɣɨð2 broydd
i-stem (inanimate) Proto-Celtic Proto-Brythonic Welsh
Singular *mori *mor môr
Plural *mor(i)yā *moreð moredd
u-stem (animate) Proto-Celtic Proto-Brythonic Welsh
Singular *sentus *hɨnt hynt
Plural *sentowes *hɨntow hyntau
u-stem (inanimate) Proto-Celtic Proto-Brythonic Welsh
Singular *beru *ber bêr
Plural *berowā *berow berau
s-stem Proto-Celtic Proto-Brythonic Welsh
Singular *tīros *tir tir
Plural *tīresa *tireð3 tiredd
Consonant stem Proto-Celtic Proto-Brythonic Welsh
Singular *karants *kar câr
Plural *karantes *karant carant4


  • 1 The plural ā-stems and plural neuter o-stems gave the same result as their respective singulars after apocope, leading to the spread of plural markers from other stem classes.
  • 2 From an earlier British plural *-iyes, which arose from analogy with the neuter i-stem plural *-iyā to parallel the plurals of the u-stem *-owes (m./f.) and *-owā (n.).
  • 3 Through the sequence of intervocalic s > h > Ø > epenthetic j > ð.
  • 4 The usual plural cerynt/ceraint was secondarily supplied with the o-stem ending *-oi > , causing final i-affection.

Adjectives edit

(put information about feminines, plurals and comparatives here)