User:Ioe bidome/Proto-Celtic

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 (R̥D > 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 *m̥, *n̥, the result is Proto-Italic *əm, *ən (> Latin em ~ im, en ~ in).
 * Word-initially, HR̥C > aRC
 * Before voiceless stops, CR̥HT > CRaT
 * CR̥HV > CaRHV
 * CR̥HC > 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):
 * 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:
 * l̥T > liT
 * r̥T > riT
 * Epenthetic *a is inserted before the remaining syllabic resonants:
 * m̥ > am
 * n̥ > an
 * l̥ > al
 * r̥ > 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