Vowel reduction in Modern Russian



12th century
Fall of the reduced yers
ǒ > ∅, ě > ∅

сънъ, sǒnǒ > сонъ, son  /  съна, sǒna > сна, sna
пьнь, pěně > пень, peń  /  пьня, pěnia > пня, pnia

19th century
Instrumental case inflection apocope
-oju > -oi, -eju > -ei

долгою зимнею дорогою, dolgoju zimneju dorogoju  >
долгой зимней дорогой, dolgoi zimnei dorogoi


2000s — 2010s
Schwa-apocope in adverbs and clitics

The ongoing fall of the reduced word-final vowels is only observable in the colloquial language. It couldn't be otherwise in the age of strict grammars and universal formal education. However, this form of language may later become standard.

Common instances of the schwa-dropping:
unstressed adverbial suffixes -o, -e > -∅
clitic particle -to > -t

просто, prosto > прост, prost
тоже, tože > тож, tož
вообще-то, voobŝe-to > вообще-т, voobŝe-t, often contracted to ваще-т, vaŝe-t
ясно, jasno > ясн, jasn
только, toĺko > тольк, toĺk, often contracted to ток, tok
наверно, naverno > наверн, navern
это, eto > эт, et
and many others

So far, these changes are generally not realized as breaking or conflicting with the written language. They belong to the informal register of both spoken and written forms, but the tendency looks stable.