Russian vowel reduction cheat sheet

Note: this is simplified to only cover phonemic mergers, disregarding more complex allophony.

1) Basic rules

Russian has two sets of orthographic vowels, one that follows hard (unpalatalised) consonants and one that follows soft (palatalised) consonants. Because of the different environments, these two sets have distinct reduction rules.

Letter	А	О	Э	Ы	У
Stressed	[a]	[o]	[ɛ]	[ɨ]	[u]
Unstressed	[ə]		[ɨ]		[u]
Letter	Я	Ё	Е	И	Ю
Stressed	[(j)a]	[(j)o]	[(j)e]	[i]	[(j)u]
Unstressed	[(j)ɪ]				[(j)u]

Note: unstressed ё is written е.

я, ё, е and ю get prefixed with [j] when they stand after a hard sign (ъ), after a soft sign (ь) or word initially.

2) э

Word initial э reduces to [ɪ] instead of [ɨ]:

этап [ɪˈtap] (stage)

3) ча, ща

Since ч and щ are always soft, a following unstressed а reduces to [ɪ]:

часы [t͡ɕɪˈsɨ] (clock, watch)
щадить [ɕːɪˈdʲitʲ] (to spare, to have mercy)

4) це, ше, же

Since ц, ш and ж are always hard, and since unstressed е can represent either an underlying /e/ or an underlying /o/, these graphies are ambiguous when unstressed:

лучше [ˈluʈʂɨ] (better)
but
тоже [ˈtoʐə] (also)

This ambiguity seems to occure mainly in word final position; elsewhere, the realisation [ɨ] is predominant.

5) ца, ша, жа

When these graphies occure in immediatly pretonic position, а reduces to [ɨ]:

лошадь [ˈloʂətʲ] (horse, nominative singular) → лошадей [ləʂɨˈdʲej] (horse, genitive plural)
двадцать [ˈdvat͡sətʲ] (twenty, nominative) → двадцати [dvət͡sɨˈtʲi] (twenty, genitive)

6) -я, -е

Final unstressed я and е are often not completely reduced when they are part of an inflectional paradigm:

	Bathhouse (singular)
Nominative	баня [ˈbanʲə]
Genitive	бани [ˈbanʲɪ]
Dative/prepositional	бане [ˈbanʲɛ]
Accusative	баню [ˈbanʲu]
Instrumental	баней [ˈbanʲɪj]

This also applies to the reflexive suffix -ся [sʲə].