Characteristics
The Brythonic branch is also referred to as P-Celtic (like Gaulish) because the Brythonic reflex of the Proto-Indo-European phoneme *kw is p as opposed to the Goidelic c. Such nomenclature usually implies an acceptance of the P-Celtic hypothesis rather than the Insular Celtic hypothesis (for a discussion, see Celtic languages).
Other major characteristics include:
- the treatment of -m, -n as -am, -an.
- initial s- followed by a vowel was changed to h-
- Welsh hen "old", hir "long", hafal "similar"
- Breton hen "ancient", hir "long", hañval "similar"
- Cornish hen "ancient", hir "long", haval "similar"
- Irish sean "old", sior "long", samail "similar"
- Brythonic retains original nasals before -t
- Breton kant "hundred" vs. Irish céad
- sp, sr, sv/sw became f, fr, chw
- *swero "toy, game" became Welsh chwarae and Breton c'hoari (but Cornish gwari)
- *srokna "nostril" became Welsh ffroen, Cornish frig and Breton froen.
- all other initial s- fell before consonants
- smeru became Welsh mêr "marrow"
- slemon became Welsh llyfn, Cornish leven and Breton levn "smooth"
- w (written u in Latin texts and ou in Greek) became gw in initial position, w internally, where in Gaelic it is f in initial position and disappears internally
- windos "white" became Welsh gwyn, Cornish gwynn, Breton gwenn
- wassos "servant, young man" became Welsh, Cornish and Breton gwas
- double plosives transformed into spirants: pp, cc, tt became f, ch (c'h), th (z) before a vowel or liquid
- cippus > Breton kef, Cornish kyf, Welsh cyff, "tree trunk"
- cattos > Breton kaz, Cornish kath, Welsh cath, "cat"
- bucca > Breton boc'h, Cornish bogh, Welsh boch, "cheek"
- single voiceless plosives and voiced d, b, and m in an intervocalic position became soft spirants
- Welsh dd, th, f
- Cornish dh, th, v
- Breton z, zh, v
Read more about this topic: Brythonic Languages