Vowel reduction in Russian

Vowel reduction in Russian differs in the standard language and dialects, which differ from one another. Several ways of vowel reduction (and its absence) are distinguished.
There are five vowel phonemes in Standard Russian. Vowels tend to merge when they are unstressed. The vowels and have the same unstressed allophones for a number of dialects and reduce to an unclear schwa. Unstressed may become more central and merge with . Under some circumstances, , , and may all merge. The fifth vowel, , may also be centralized but does not typically merge with any of the other vowels.
Other types of reduction are phonetic, such as that of high vowels ( and ), which become near-close so ('to play') is pronounced , and ('man') is pronounced .
Russian orthography does not reflect vowel reduction, which can confuse foreign-language learners.
General description.
The five Russian vowels in unstressed position show two levels of reduction:
The allophonic result of the reduction is also heavily dependent on the quality of the preceding consonant as well as the lack thereof. Thus the reduction is further grouped into three types according to the environment:
The unstressed vowels also may be grouped in series, reflecting similar patterns of the reduction:
Or otherwise:
High vowels.
Two high vowels and are usually thought to undergo no reduction. However, on the phonetic level they show allophonic centralization, particularly under the influence of the preceding or the following consonants. The unstressed high back vowel is either (after hard consonants, written ) or (after soft consonants, written , except , ). The unstressed high front vowel is either or (after soft consonants, written ), or or (after hard consonants, written , except , ). Nevertheless, in rapid colloquial speech they both may be reduced to schwa , for example, ('kind', instrumental case, singular masculine-neuter) versus ('kind', prepositional case, sg. masc.-neut.): the case ending //-im// in the former may surface as like the case ending //-om//, thus leading to the merger of and ; or ('they do') versus ('he/it does'): both may surface as or .
Back vowels.
Other than in Northern Russian dialects Russian speakers have a strong tendency to merge unstressed and , called "akanye" (). It contrasts with "okanye" () pronunciations. It works in Standard Russian as follows:
Across certain word-final suffixes, the reductions do not completely apply. In certain suffixes, after palatalised consonants and , and (which is written as ) can be distinguished from and from each other: ('field' nominative singular neuter) is different from ('field' singular genitive), and the final sounds differ from the realisation of in that position.
There are a number of exceptions to the above comments regarding the "akanye":
Front vowels.
The main feature of front vowel reduction is "ikanye" (), the merger of unstressed with . Because has several allophones (depending on both stress and proximity to palatalised consonants), unstressed is pronounced as one of these allophones and not actually as the close front unrounded vowel. For example, ('seeds') is pronounced , ('price') .
In registers without the merger ("yekanye" or ), unstressed is more retracted. Even then, however, the distinction between unstressed and unstressed is most clearly heard in the syllable just before the stress. Thus, ('to add to') contrasts with ('to betray'). The two are pronounced and respectively. "Yekanye" pronunciation is coupled with a stronger tendency for both unstressed and to be pronounced the same as .
Speakers may switch between the two types of pronunciation because of various factors, the most important factor likely being speed of pronunciation.
Yakanye.
"Yakanye" () is the pronunciation of unstressed and following palatalised consonants preceding a stressed syllable as rather than ( is pronounced , not ).
This pronunciation is observed in the Belarusian language and most Southern Russian dialects, as expressed in a quip (with liberal "yakanye"):
The example also demonstrates other features of Southern dialects: palatalised final in the 3rd person forms of verbs, instead of and instead of (in some places) and , clear unstressed in place of or .
Spelling.
Vowel reduction makes some words have spellings that contradict their etymology, such as (instead of , which was standard spelling before the Ushakov Dictionary), (instead of , the standard spelling until the reform of 1956), (instead of , with a long history).
In the closely related Belarusian language, original has merged with as in Standard Russian, but the reduced pronunciation is reflected in the spelling.