1. merge centum: [+palatal +velar] → [-palatal +velar]
    *ḱléwos*klewos ‘fame’
  2. dental separation and simplification: TT → TsT → *ss
    *bʰreud-tós*bʰreussós ‘broken’
  3. metathesis of thorn clusters: TK > KT
    *h₂rtkos*h₂rktos ‘bear’
  4. loss of laryngeals before vowel (triple reflex, Greek-style)
    *h₁e → *e~i
    *h₂e → *a
    *h₃e → *o
  5. loss of laryngeal after vowel, same as above but lengthening
    *eh₁ → *ē
    *eh₂ → *ā
    *eh₃ → *ō
  6. epenthetic *ə inserted before syllabic resonants
    *septṃ*septəm ‘seven’
  7. loss of laryngeal between two consonants: (CHC → CəC)
    *H → *ə (except: #_R where *H → h)
  8. CVHC → CV̄C
  9. Labiovelars reanalysed as sequence of plosive + *w
  10. *s + plosive → *ss / V_V, V_
    *st, *sk → *ss
  11. *m becomes *n before dentals and word finally.
  12. nasal + velar → *nn
  13. PT, KT join TT in → *ss
    *kh₂ptós*kəssós ‘taken’
  14. merger of *ə and short *a
  15. fricativization and devoicing of syllable-initial velar consonants before *w, *r, *l
  16. stress is retracted one step
  17. lengthening of *a in closed and stressed syllables
  18. labiovelar sequences simplify to *w / V_V
    *ákwā → *áwā ‘water’
  19. raising of *o after *w
    *déywos*déywus ‘god’
  20. [-voice +stop] → [+voice +stop] / R_V
  21. lowering of *e → *æ when following syllable has a low vowel. (active surface filter)
  22. *s → *z / V_{V #}
  23. *h → Ø / #_{l r}
  24. innovation of future tense from desiderative -s- formation.
    *kā́psyeō ‘I will seize’ ( < *keh₂p-s-yé-oh₂)
  25. loss of *w before *u
    *wī́wus → *wī́uz
  26. secondary athematic endings are added to the imperfective present and future 1sg and replace 1pl, 2pl, 3pl.
    *kā́pyeōn < (*kh₂p-yé-oh₂-m); *kā́psyeōn ( < *keh₂p-s-yé-oh₂-m)
    *kāpyéme < (*kh₂p-ye-mé)
  27. *ō → *ā
    *kā́psyeōn*kā́psyeān
  28. P K → f x / V_s
    *pā́ksyeān*pā́xsyeān ‘I will fasten’ ( < *ph₂ḱ-s-yé-oh₂-m)
  29. *e → *æ / C_aC
    *bʰóweyeān*bʰówæyæān ‘I warn’ ( < *bʰogʷ-éye-oh₂-m)
  30. Shift to strong initial expiratory stress
  31. *p *t *k → *β *ð *ɣ / V_V, R_
    *kā́pyæān*kā́βyæān ‘I seize’
  32. *z → *r / V_V, V_#
    *wī́uz*wīur ‘alive’
  33. merger of locative and instrumental cases
  34. *x → *s / _s
    *péxsyæān*péssyæān ‘I will slap’ ( < *peḱ-s-yé-oh₂-m)
  35. breaking of stressed open *é → *yá
    *déyur*dyáyur
  36. end of *e → *æ lowering
  37. new case endings: essive -ta, comitative -we [1]
  38. fortition of *β *ð *ɣ → *bʰ *dʰ *gʰ
    *néβāt*nébʰāt ‘nephew’
  39. unstressed *ē → ai (operating during period of contraction)
    *pádʰēr*pádʰair ‘father’
  40. contraction
    *o + *e → *ē
    *e + *o → *ō
    *æ, *a + *a, *ā → *ā
  41. medial -y- loss
    *dyáyusta*dyáusta ‘like a god’
  42. loss of initial h in clusters.
    *hrāra*rāra ( < *Hroseh₂ )
  43. shortening of long final vowels after a stressed syllable
    *wórān*wóran ‘prepare’ ( < *gʷʰor-éy-oh₂-m)
  44. vocalisation of semi-vowels / #C_V
    *dyáur*diáur
  45. V:, V:C and VCC become standard
  46. : *wóran*wṓrann
  47. *ew → *u:
    *lewmana*lūmana 'first light of the day' ( < *léwk-mn-eh₂)

break for ease of edit

  1. *æ → *e
  2. 1sg.fut is de-iotated by analogy with the 1sg.pres
    *kā́ssjan*kā́ssan ‘I will seize’
  3. loss of middle endings with -r, forms with secondary middle endings win out
    *bʰriágar*bʰriága ‘I am brought to ruin’ ( < *bʰregh₂ér)
    *bʰriágror*bʰriágandho ‘they are brought to ruin’
  4. Verb raising (i.e. fronting) occurs more frequently. Transitive verbs also raise their argument after them.
    *kā́ssan paldháron niábhas diáusta lúmanai ‘(Truly!) I will seize the settlement (of my) nephew as a (living) god by the first light of day’ ( < *kh₂p-s-yé-oh₂-m pḷth₂róm népōts deywós-?ta? léwk-mn-ey)
    *pā́rssat sān so ‘He is asking her’ vs. *so sān pā́rssat ‘he asks her’
  5. A general trend of reanalysing collective nouns as singular feminines intensifies.
    *palla ‘several fortifications’ → *palla ‘city’ ( < *tpelHh₂)
    *walla ‘set of wheels’ → *walla ‘wagon’ ( < *kʷékʷlh₂)
  6. syllable bounding *n is lengthened
    *kiasmanar*kiasmannar ‘outriders, messengers’ ( < *kérs-mṇ-es through contamination with *kérs-mṇ-h₂ ‘group of messengers’)
  7. loss of unstressed, word-final short vowels in words where n(s) => 3.
    *aliendhi*aliendh ‘they feed’ ( < *h₂oléyenti)
    *bʰriágandho*bʰriágandh ‘they are brought to ruin’

References

  1. ^
    *dyáyur 'god'
    Number Singular Plural
    Nominative *dyáyur *dyáywer
    Vocative *dyáyu *dyáywer
    Genitive *dyáyuryor *dyáywān
    Accusative *dyáyun *dyáyuns
    Dative *dyáywei *dyáyuybhor
    Ablative *dyáywiad *dyáyuybhor
    Locative-Instrumental *dyáywei *dyáyuysu
    Essive *dyáyusta *dyáyuysta
    Comitative *dyáyuwe *dyáywezwe