Most Russian consonants come in pairs, of one ‘soft’ consonant and one ‘hard’ consonant. A soft consonant is one that is palatalised—pronounced with the centre of the tongue raised towards the roof of the mouth (palate). A hard consonant is a consonant that is not soft.
One example of a distinction in English between a hard consonant and a soft consonant is in English. In onion, the 1st <n> is soft (sounding like <n> pronounced simultaneously with <y>, as in yes) and the 2nd <n> is hard.
Pairs of hard and soft consonants
The distinction between hard and soft consonants is of little importance in English, but it is pervasive in Russian. Table 1 lists the pairs of hard and soft consonants in Russian. Each cell lists a soft consonant (marked with a superscript j) below its hard pair. Instead of superscript j, some transliteration conventions use an apostrophe <’> to mark palatalisation.
| Labial | Dental | Velar | |
| Stop (unvoiced) | p pʲ | t tʲ | k kʲ |
| Stop (voiced) | b bʲ | d dʲ | g gʲ |
| Fricative (unvoiced) | f fʲ | s sʲ | x xʲ |
| Fricative (voiced) | v vʲ | z zʲ | |
| Lateral approximant | l lʲ | ||
| Trill | r rʲ | ||
| Nasal | m mʲ | n nʲ |
In native words, the hard velars /k, g, x/ appear only before the back vowels /a, o, u/ or at the end of a word. The soft velars /kj, gj, xj/ appear only before the front vowels /i, e/.
Unpaired consonants
In native words, a few soft consonants (listed in table 2) have no hard counterpart and a few hard consonants (listed in table 3) have no soft counterpart. The counterparts do exist in some borrowed words or in some dialects.
| Articulation | Consonant | Spelling |
| Voiceless palatal fricative | /ʃʲː/ | щ |
| Voiceless palatal affricate | /tʃʲ/ | ч |
| Palatal approximant | /j/ | Marked by: (1) following vowel (table 4) (2) <й> if final |
/ʃʲː/ is like a long version of the English sound written as <sh> in English fresh. /tʃʲ/ is like English <ch> in cheese.
Around St Petersburg, a now obsolete pronunciation of <щ> was /ʃʲtʃʲ/—like the English sequence written as <sh_ch> in fresh cheese.
| Articulation | Consonant | Spelling |
| Unvoiced post-alveolar fricative | ʃ | ш |
| Voiced post-alveolar fricative | ʒ | ж |
| Unvoiced dental / alveolar affricate | ts | ц |
/ʃ/ is like a hard (unpalatalised) version of the English sound written as <sh> in English fresh. Its voiced pair /ʒ/ is like a hard (unpalatalised) version of the English sound written as <s> in English measure or as <z> in azure.
Marking consonants as soft
The Russian version of the Cyrillic alphabet uses 2 different series of letters for vowels to mark whether the preceding consonant is hard or soft (table 4).
| Letter after hard consonant | Sound | Letter after soft consonant | Sound |
| a | /a/ | я | /ja/ |
| э | /e/ | e | /je/ |
| ы | /ɨ/ | и | /i/ |
| o | /o/ | ё | /jo/ |
| y | /u/ | ю | /ju/ |
Comments on the letters:
- <э> appears only in a few native words—mainly related to этo ([ɛto], ‘this’)—and some borrowed words.
- <и>, unlike the other soft-series vowel letters, represents a vowel /i/ having no initial /j-/.
Opinions vary on whether /i/ and /ɨ/ are 2 different phonemes, or just allophones of a single phoneme.
For more on the high central vowel /ɨ/, please see https://languagemiscellany.com/2021/08/is-russian-difficult-for-english-speakers/ - <ё> is generally replaced by <e>, except in texts written for learners and in lexicography, and except to distinguish confusable words—such as bce (‘all’, plural) and bcё (‘everything’).
The sound /jo/ spelled by <ё> arose originally several centuries ago when stressed /je/ did not immediately precede a soft consonant. However, later analogical changes led to some cases of /jo/ in other environments and led to some earlier cases of /jo/ reverting to /je].
Vowels are more fronted after or before palatalised consonant—and fronted even more between them. Yanushevskaya and Bunčić (2015) and Cubberley (2002, section 3.2.3.2) give details.
Consonants at the end of a syllable
If no vowel follows a soft consonant, softness is marked by placing a soft sign <ь> immediately after that consonant. As I have said before, I find it very difficult to pronounce Russian soft consonants if no vowel follows them. Is Russian difficult for English speakers? – Language Miscellany
The unpaired hard consonants /ʃ/ and /ʒ/ were soft until some time between the 12th and 14th centuries and the consonant /ts/ until somewhat later. Sometimes, a soft sign <ь> occurs for historical reasons after some unpaired hard consonants, for example:
- in the 2nd person singular present tense ending of verbs.
- in the nominative singular of feminine nouns ending in one of these consonants.
A complex set of principles determines whether consonants are hard or soft within a cluster of consonants. Several of the sources listed below discuss those principles.
Spelling rules
Although /ʃ, ʒ, ts/ are always hard;
- /e/ following those consonants is spelled as <e> (not as <э>) and following /ɨ/ is sometimes spelled as <и> (not as <ы>).
- unstressed /o/ following /ʃ, ʒ/ is spelled as <e>.
Although /ʃʲː/ and /tʃʲ/ are always soft:
- a following /a/ or /u/ is spelled as <a, y>, not as <я, ю>.
- a following /o/ is spelled as <o> (not as <ё >): in noun or adjective endings; in the diminutive suffix /ok/; and in words whose inflected forms all contain only the stressed form of the vowel.
References
Illustrations of the IPA: Russian, Irena Yanushevskaya and Daniel Bunčić, Journal of the International Phonetic Association (2015) russian.pdf
Introduction to Russian Phonology and Word Structure, William S Hamilton (1980)
Russian: A Linguistic Introduction, Paul Cubberley (2002)
What’s in a Russian Word?, Ian Press (2000)
Russian, Alan Timberlake, in The Slavonic Languages, edited by Bernard Comrie and Greville G Corbett (1993)
A Linguistic History of Russia: To the End of the Eighteenth Century, AP Vlasto (1986)
The Slavic Languages, Roland Sussex and Paul Cubberley (2006)
Common and Comparative Slavic: Phonology and Inflection; with special attention to Russian, Polish, Czech, Serbo-Croatian and Bulgarian, Charles E Townsend and Lara A Janda (1996)