2018-08
axtk

Vowel reduction in Modern Russian

Previously

12th century
Fall of the reduced yers
ъ > , ь >

съна > сна
пьня > пня

19th century
Instrumental case inflection apocope
-ою > -ой, -ею > -ей

долгою зимнею дорогою > долгой зимней дорогой

Today

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 become standard later.

Common instances of the schwa-dropping:
unstressed adverbial suffixes , > -∅
clitic particle -то >

просто > прост
тоже > тож
вообще-то > вообще-т, ваще-т
ясно > ясн
только > тольк, ток
наверно > наверн
это > эт

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.