So. The thing I wanted to post in this thread of mine is to do with Old Irish, Proto-Brythonic, and Common Brittonic. (There should be a "CELTIC" thread. If not, then this thread will just expand.)
Old Irish (the ancestor of Scottish) had a complex system of lenition and mutation.
Lenition in essence is pronouncing a consonant in a more relaxed way than usual (making the consonants "more sonorous").
(χ, ν= lenited versions of the respective consonants)
The noun declensions use these instead of simple recognizable endings.
(NGDAV): ech, eichᴸ, euch(eoch)ᴸ, echᴺ, àl eichᴸ, which simplified into Irish each, eich, each, a each.
These in turn had gone through sound changes from Primitive Irish and Proto-Celtic:
Old Irish: ech, eichᴸ, euch (eoch)ᴸ, echᴺ, àl eichᴸ
Primitive Irish: *eχʷah, eχʷi, eχʷu, eχʷan, *eχʷe
Proto-Celtic: *ekʷos, ekʷi, (older ekʷosio), *ekʷui,-u, ud, *ekʷom, *ekʷe
(Not all of the Ogham inscriptions are fully understood.)
The languages are split up either as Gallo-Brittonic or Insular and Continental. Gallo-Brittonic inserts that Gaulish and Brittonic languages had a common ancestor apart from the others, the Goidelic langs. Shared innovations that Goidelic lacks:
- Proto-Celtic kʷ > Gallo-Brittonic p, or in voiced form b (e.g. Gaulish mapos, Welsh mab ≠ Irish mac)
- Proto-Celtic mr and ml > Gallo-Brittonic br and bl (e.g. Gaulish broga, Welsh, Breton bro ≠ Old Irish mruig)
- Proto-Celtic wo, we > Gallo-Brittonic wa (e.g. Gaulish uassos, Welsh gwass ≠ Old Irish foss)
- Proto-Celtic ɡʷ > Gallo-Brittonic w
- Early loss of g between vowels in both Gaulish and Brittonic
- Proto-Celtic dj between vowels tended to give Gallo-Brittonic j
Insular Celtic would assert that Goidelic and Brythonic had a common ancestor and development, with Gaulish and Brythonic having similar independent innovations and mutually influencing each other through contact between the groups.
As one of my friends says, both make sense. Another friend of mine,
Combrogîs, says that what exactly happened more complex than either hypothesis.
By the way, the Proto-Celtic present paradigm for "to be" had ablaut (3 sg. *esti: 3 pI. *senti).
*Est.