| 16 Extended West Papuan | 16.1.5 Proto-Tabla-Sentani to Tabla | oi → oe | 
| 17 Indo-European | 17.5.1 Proto-Indo-European to Old Irish | oːi → uː / _# | 
| — {ai,oi} → iː / _# | 
| 17.5.2 Proto-Celtic to Middle Welsh | uː {oi,ɔː} → yː uː | 
| 17.6 Proto-Indo-European to Dacian | oi wo wj ow → ai wa vi aw | 
| 17.7 Proto-Indo-European to Common Germanic | ei oi → iː ai | 
| eːi {oːi,aːi} → eː oː (?) | 
| 17.7.2.1.9 Early Northern Middle English to Scots | — ai oi ui ei au ou iu ɛ(o)u → eː oe əi iː {ɑː,ɔː} ʌu ju j(ʌ)u | 
| 17.11 Proto-Indo-European to Proto-Slavic | {ai,oi} → i / j_ | 
| {ai,oi} → æː | 
| {aːi,oːi} → {æː,a} (the former seems to be more common) | 
| oi o → i ъ / “Sometimes in final syllables” | 
| 17.12.1.1 Proto-Indo-European to Latin | oj → oi → oe → uː | 
| ei oi ou → iː eː uː / %(C)(C)_ when unstressed | 
| {ai,ei,oi} → ei → iː / _(C)(C)# | 
| 17.12.1.1.1 Classical Latin vs. Vulgar Latin | {i,eː,oi} → e | 
| 17.12.1.1.3 Latin to French | oi → wɛ → wa | 
| oı̃ → wɛ̃ | 
| 30 Niger-Congo | 30.3.1.1.3 Proto-Gbe to Proto-Fon | oi ɔi ɔ̃i {a,ɛ}i {ɛ̃,ẽ}i ei → oe ɔɛ ɔ̃ɛ̃ ɛɛ ɛ̃ɛ̃ ee | 
| 42 Uralic | 42.1.1.1 Proto-Finnic to Proto-Finnish | oi → o / unstressed | 
| 46 Vowel Shifts | 46.5 Old English-to-Scots Vowel Shifts | ai oi ui ei au ou iu ɛ(o)u → eː oe əi iː {ɑː,ɔː} ʌu ju j(ʌ)u | 
| 46.10 Late Proto-Finnic to Savonian Vowel Shift | ei oi øi → eː oe øe |