In the pronunciation of the Russian language, several ways of vowel reduction (and its absence) are distinguished between the standard language and dialects. Russian orthography most often does not reflect vowel reduction, which can confuse foreign-language learners, but some spelling reforms have changed some words.
There are five vowel phonemes in Standard Russian. Vowels tend to merge when they are unstressed. The vowels /a/ and /o/ have the same unstressed allophones for a number of dialects and reduce to an unclear schwa /ə/. Unstressed /e/ may become more central and merge with /i/. Under some circumstances, /a/, /e/, /i/ and /o/ may all merge. The fifth vowel, /u/, 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 the high vowels (/i/ and /u/), which become near-close. Thus, игра́ть ('to play') is pronounced [ɪˈɡratʲ], and мужчи́на ('man') is pronounced [mʊˈɕːinə].