Russian phonology

This article discusses the phonological system of standard Russian based on the Moscow dialect (unless otherwise noted). For discussion of other dialects, see Russian dialects. Most descriptions of Russian describe it as having five vowel phonemes, though there is some dispute over whether a sixth vowel,, is separate from. Russian has 34 consonants, which can be divided into two sets: Russian has vowel reduction in unstressed syllables. This feature is found in English, but not in most other Slavic languages, such as Polish, Czech, and Serbo-Croatian.
 * hard (твёрдый ) or plain
 * soft (мягкий ) or palatalized

Vowels
Russian has five or six vowels in stressed syllables, and in some analyses, but only two or three vowels in unstressed syllables:  after hard consonants and  after soft ones.

A long-standing dispute among linguists is whether Russian has five vowel phonemes or six; that is, scholars disagree as to whether constitutes an allophone of  or if there is an independent phoneme. The five-vowel analysis, taken up by the Moscow school, rests on the complementary distribution of and, with the former occurring after hard (non-palatalized) consonants and  elsewhere. The six-vowel view, held by the Saint-Petersburg (Leningrad) phonology school, points to several phenomena to make its case:
 * Native Russian speakers' ability to articulate in isolation (for example, in the names of respective letters, $⟨и⟩$ and $⟨ы⟩$),
 * Rare instances of word-initial (including the minimal pair икать 'to produce the sound и' and ыкать 'to produce the sound ы'), as well as borrowed names and toponyms, like Ыб, the name of a river and several villages in the Komi Republic.
 * Morphological alternations like готов ('ready' predicate, m.) and готовить  ('to get ready' trans.) between palatalized and non-palatalized consonants.

The most popular view among linguists (and that taken up in this article) is that of the Moscow school, though Russian pedagogy has typically taught that there are six vowels (the term phoneme is not used).

Reconstructions of Proto-Slavic show that *i and *y (which correspond to  and ) were separate phonemes. On the other hand, numerous alternations between the two sounds in Russian indicate clearly that at one point the two sounds were reanalyzed as allophones of each other.

Allophony
Russian vowels are subject to considerable allophony, subject to both stress and the palatalization of neighboring consonants. In most unstressed positions, in fact, only three phonemes are distinguished after hard consonants, and only two after soft consonants. Unstressed and  merge (a phenomenon known as akan'je); unstressed  and  merge (ikan'je); and all four unstressed vowels merge after soft consonants, except in absolute final position in a word. None of these mergers are represented in writing.

Front vowels
When a preceding consonant is hard, is retracted to. Formant studies in demonstrate that  is better characterized as slightly diphthongized from the velarization of the preceding consonant, implying that a phonological pattern of using velarization to enhance perceptual distinctiveness between hard and soft consonants is strongest before. When unstressed, becomes near-close; that is,  following a hard consonant and  in most other environments. Between soft consonants, both stressed and unstressed are raised, as in пить  ('to drink') and маленький  ('small'). When preceded and followed by coronal or dorsal consonants, is fronted to. After a labial + cluster,  is retracted, as in плыть  ('to float'); it is also slightly diphthongized to.

In native words, only follows unpaired (i.e. the retroflexes and ) and soft consonants. After soft consonants (but not before), it is a mid vowel ( or ), while a following soft consonant raises it to. Another allophone, an open-mid occurs word-initially and never before or after soft consonants (hereafter  is represented without the diacritic for simplicity). Preceding hard consonants retract to  and  so that жест ('gesture') and цель ('target') are pronounced  and  respectively.

In words borrowed from other languages, rarely follows soft consonants; this foreign pronunciation often persists in Russian for many years until the word is more fully adopted into Russian. For instance, шофёр (from French chauffeur) was pronounced in the early twentieth century, but is now pronounced. On the other hand, the pronunciations of words such as отель ('hotel') retain the hard consonants despite a long presence in the language.

Back vowels
Between soft consonants, becomes, as in пять  ('five'). When not following a soft consonant, is retracted to  before  as in палка  ('stick').

For most speakers, is a mid vowel but it can be more open for some speakers. Following a soft consonant, is centralized to  as in тётя  ('aunt').

As with the other back vowels, is centralized between soft consonants, as in чуть  ('narrowly'). When unstressed, becomes near-close.

Unstressed vowels
Russian unstressed vowels have lower intensity and lower energy. They are typically shorter than stressed vowels and tend to merge: These mergers do not occur in all dialects. The merger of unstressed and  in particular is less universal than that of unstressed  and  (e.g. speakers near the border with Belarus have the latter but not the former merger, distinguishing between лиса́ ('fox') and леса́ ('forests'), прожива́ть ('to reside') and прожева́ть ('to chew'), etc.). The distinction between unstressed and  is codified in some pronunciation dictionaries.
 * and merge in most unstressed positions (e.g. валы 'bulwarks' and волы 'oxen' are pronounced ).
 * Likewise, and  merge in most unstressed positions (e.g. лиса 'fox' and леса 'forests' are pronounced ).
 * All four merge in most unstressed positions after soft consonants.

As a result, in most unstressed positions, only three vowel phonemes are distinguished after hard consonants ( vs. vs. ), and only two ( vs. ) after soft consonants. For the most part, Russian orthography (as opposed to that of closely related Belarusian) does not reflect vowel reduction.

Vowel mergers
In terms of actual pronunciation, there are at least two different levels of vowel reduction: vowels are less reduced when a syllable immediately precedes the stressed one, and more reduced in other positions. This is particularly visible in the realization of unstressed and, where a less-reduced allophone  contrasts with a more-reduced allophone.

The pronunciation of unstressed is as follows:


 * 1) (sometimes transcribed $⟨ы⟩$) appears in the following positions:
 * 2) *In the syllable immediately before the stress, when a hard consonant precedes. Example: паром ('ferry'), трава  ('grass').
 * 3) *In absolute word-initial position.
 * 4) *Adjacent to a hiatus, when the same sound occurs on both sides of the hiatus (written $⟨е⟩$, $⟨⟩$, $⟨aa⟩$, or $⟨ao⟩$). Example: соображать ('to use common sense/to reason').
 * 5) appears elsewhere, when a hard consonant precedes. Example: облако  ('cloud'),.
 * 6) When a soft consonant or precedes, both  and  merge with  and are pronounced as . Example: язык  'tongue').  is written as $⟨oa⟩$ in these positions.
 * 7) *This merger also tends to occur after formerly soft consonants now pronounced hard, where the pronunciation occurs. This always occurs when the spelling uses the soft vowel variants, e.g. жена  ('wife') (with underlying ).  However, it also occurs in a few word roots where the spelling writes a hard . Examples:
 * 8) **жал- 'regret': e.g. жале́ть ('to regret'), к сожалéнию  ('unfortunately').
 * 9) **лошадь 'horse', e.g. лошаде́й, (pl. gen. and acc.).
 * 10) **-дцать- in numbers: e.g. двадцати́ ('twenty [gen., dat., prep.]'), тридцатью́  ('thirty [instr.]').
 * 11) **ржано́й ('rye [adj.]').
 * 12) **жасми́н ('jasmine').
 * 13) These processes occur even across word boundaries as in под морем ('under the sea').

The pronunciation of unstressed is  after soft consonants and, and word-initially (эта́п  ('stage')), but  after hard consonants (дышать  ('to breathe')).

There are a number of exceptions to the above vowel-reduction rules:
 * Vowels may not merge in foreign borrowings, particularly with unusual or recently borrowed words (e.g. радио, 'radio').  In such words, unstressed  may be pronounced as, regardless of context and word pairs like эмигра́нт/иммигра́нт or эмити́ровать/имити́ровать differ in pronunciation.
 * Across certain word-final inflections, the reductions do not completely apply. For example, after soft or unpaired consonants, unstressed, and  of a final syllable may be distinguished from each other. For example, жи́тели  ('habitants') contrasts with both (о) жи́теле  ('[about] an habitant') and жи́теля.
 * If the first vowel of $⟨oo⟩$, or $⟨e⟩$ belongs to the conjunctions но- ('but') or то ('then'), it is not reduced, even when unstressed.
 * In loanwords, unstressed does not merge with  in initial position or after vowels, so word pairs like эмигрант/иммигрант or эмитировать/имитировать differ in pronunciation.

Other changes
Unstressed is generally pronounced as a lax (or near-close), e.g. мужчина  ('man'). Between soft consonants, it becomes centralized to, as in ютиться ('to huddle').

Note a spelling irregularity in of the reflexive suffix -ся: with a preceding -т- in third-person present and a -ть- in infinitive, it is pronounced as, i.e. hard instead of with its soft counterpart, since  (normally spelled with $⟨oa⟩$) is traditionally always hard. In other forms both pronunciations and  alternate for a speaker with some usual form-dependent preferences.

In weakly stressed positions, vowels may become voiceless between two voiceless consonants: выставка ('exhibition'), потому что  ('because'). This may also happen in cases where only the following consonant is voiceless: череп ('skull').

Phonemic analysis
Because of mergers of different phonemes in unstressed position, the assignment of a particular phone to a phoneme requires phonological analysis. There have been different approaches to this problem:


 * The Saint Petersburg phonology school assigns allophones to particular phonemes. For example, any  is considered as a realization of.
 * The Moscow phonology school treats as either  or, depending on morphological alternations or etymology. To make a determination, one must seek out instances where an unstressed morpheme containing  in one word is stressed in another word.  Thus, if the word  ('shafts') shows an alternation with  ('shaft'), then this instance of  is an allophone of .  Meanwhile,  ('oxen') alternates with  ('ox'), showing that this instance of  is an allophone of .  If there are no alternations between stressed and unstressed syllables for a particular morpheme, then the assignment is based on etymology.
 * Some linguists prefer to avoid making the decision. Their terminology includes strong vowel phonemes (the five) for stressed vowels plus several weak phonemes for unstressed vowels: thus, represents the weak phoneme, which contrasts with other weak phonemes, but not with strong ones.

Diphthongs
Russian diphthongs all end in a non-syllabic, an allophone of and the only semivowel in Russian. In all contexts other than after a vowel, is considered an approximant consonant. Phonological descriptions of may also classify it as a consonant even in the coda. In such descriptions, Russian has no diphthongs.

The first part of diphthongs are subject to the same allophony as their constituent vowels. Examples of words with diphthongs: яйцо ('egg'), ей  ('her' dat.), действенный  ('effective'). (written -$⟨oo⟩$ or -$⟨ц⟩$) is a common inflexional affix of adjectives, participles, and nouns, where it is often unstressed; at normal conversational speed, such unstressed endings may be monophthongized to.

Consonants
$⟨ий⟩$ denotes palatalization, meaning the center of the tongue is raised during and after the articulation of the consonant. Phonemes that have at different times been disputed are enclosed in parentheses.


 * Notes
 * Most consonants phonemes come in hard–soft pairs (exceptions are listed below). There is a marked tendency of Russian hard consonants to be velarized, though this is a subject of some academic dispute. Velarization is clearest before the front vowels and.
 * and are always hard in native words (even if spelling contains a "softening" letter after them, as in жена, шёлк, жить, мышь, жюри, парашют etc.), and for most speakers also in foreign proper names, mostly of French or Lithuanian origin (e.g. Гёльджюк, "Жён Африк", Жюль Верн, Герхард Шюрер, Шяуляй, Шяшувис). Long phonemes  and  do not pattern in the same ways that other hard–soft pairs do.
 * is generally listed among the always-hard consonants, however certain foreign proper names, including those of Polish, Ukrainian, or Lithuanian origin (e.g. Цюрих, Цюрупа, Пацюк, Цявловский), as well as loanwords (e.g., хуацяо, from Chinese) contain a soft . The phonemicity of a soft is supported by neologisms that come from native word-building processes (e.g. фрицёнок, шпицята).
 * and are always soft.
 * is also always soft. A formerly common pronunciation of indicates the sound may be two underlying phonemes:  and, thus  can be considered as a marginal phoneme. In today's most widespread pronunciation,  appears (instead of ) for orthographical -зч-/-сч- where ч- starts a words's root, and -з/-с belongs to a preposition or a "clearly distinguisheable" prefix (e.g. без часов , 'without a clock'; расчертить , 'to rule'); in all other cases  is used (щётка, грузчик, переписчик, счастье, мужчина, исщипать, расщепить etc.)
 * was always soft few decades ago; now it is generally replaced with a geminated hard (or with spelling-motivated  in the case of the root -дожд-: дождя, дожди, дождик, дождливый etc.). The status of  as a phoneme is also marginal since it may derive from an underlying  or . For more information, see alveolo-palatal consonant and retroflex consonant.
 * is a somewhat concave apical postalveolar. It may be described as retroflex, e.g. by, but this is to indicate that it is not laminal nor palatalized; not to say that it is subapical. differs from  only by being voiced.
 * Hard are laminal denti-alveolar, Unlike in many other languages,  does not become velar  before velar consonants.
 * Hard has been variously described as pharyngealized apical alveolar  and velarized laminal denti-alveolar . Because of that, some scholars transcribe it  even in phonemic transcription. This article uses  for simplicity.
 * Hard is postalveolar  and is typically a trill.
 * Soft is an apical dental tap  or, less often, an apical dental trill.
 * Soft are laminal alveolar . As indicated in the transcription, in case of the first two the tongue is raised enough to produce slight frication.
 * Soft is either laminal alveolar  or laminal denti-alveolar.
 * are dental, i.e. dentalized laminal alveolar. They are pronounced with the blade of the tongue very close to the upper front teeth, with the tip of the tongue resting behind lower front teeth.
 * A marginal phoneme occurs instead of  in certain interjections: ага, ого, угу, эге, о-го-го, э-ге-ге, гоп. (Thus, there exists a minimal pair of homographs: ага  'aha!' vs ага  'agha'). The same sound  can be found in бухгалтер (spelled $⟨ый⟩$, though in цейхгауз, $⟨⟩$ is ), optionally in габитус and in a few other loanwords. Also optionally (and less frequently than a century ago)  can be used instead of  in certain religious words (a phenomenon influenced by Church Slavonic pronunciation): Бога, Богу... (declension forms of Бог 'God'), Господь 'Lord' (especially in the exclamation Господи! 'Oh Lord!'), благой 'good'.
 * Some linguists (like I. G. Dobrodomov and his school) postulate the existence of a phonemic glottal stop . This marginal phoneme can be found, for example, in the word не-а . Claimed minimal pairs for this phoneme include суженный 'narrowed' (a participle from сузить 'to narrow', with prefix с- and root -уз-, cf. узкий 'narrow') vs суженый  'betrothed' (originally a participle from судить 'to judge', now an adjective; the root is суд 'court') and с Аней  'with Ann' vs Саней  '(by) Alex'.

There is some dispute over the phonemicity of soft velar consonants. Typically, the soft–hard distinction is allophonic for velar consonants: they become soft before front vowels, as in короткий ('short'), unless there is a word boundary, in which case they are hard (e.g. к Ивану  'to Ivan'). Hard variants occur everywhere else. Exceptions are represented mostly by:
 * Loanwords:
 * Soft: гёзы, гюрза, гяур, секьюрити, кюре, кяриз, санкхья, хянга;
 * Hard: кок-сагыз, гэльский, акын, кеб, хэппенинг.
 * Proper nouns of foreign origin:
 * Soft: Алигьери, Гёте, Гюнтер, Гянджа, Джокьякарта, Кёнигсберг, Кюрасао, Кяхта, Хьюстон, Хёндэ, Хюбнер, Пюхяярви;
 * Hard: Мангышлак, Гэри, Кызылкум, Кэмп-Дэвид, Архыз, Хуанхэ.

The rare native examples are fairly new, as most them were coined in the last century:
 * Soft: forms of the verb ткать 'weave' (ткёшь, ткёт etc., and derivatives like соткёшься); догёнок/догята, герцогёнок/герцогята; and adverbial participles of the type берегя, стерегя, стригя, жгя, пекя, секя, ткя (it is disputed whether these are part of the standard language or just informal colloquialisms);
 * Hard: the name гэ of letter $\langleхг\rangle$, acronyms and derived words (кагебешник, днепрогэсовский), a few interjections (гы, кыш, хэй), some onomatopoeic words (гыгыкать), and colloquial forms of certain patronyms: Олегыч, Маркыч, Аристархыч (where -ыч is a contraction of standard language's patronymical suffix -ович rather than a continuation of ancient -ич).

In the mid-twentieth century, a small number of reductionist approaches made by structuralists put forth that palatalized consonants occur as the result of a phonological processes involving (or palatalization as a phoneme in itself), so that there were no underlying palatalized consonants. Despite such proposals, linguists have long agreed that the underlying structure of Russian is closer to that of its acoustic properties, namely that soft consonants are separate phonemes in their own right.

Final devoicing
Voiced consonants (, and ) are devoiced word-finally unless the next word begins with a voiced obstruent. , in addition to becoming voiceless, also lenites to in some words, such as бог.

Voicing
Russian features a general retrograde assimilation of voicing and palatalization. In longer clusters, this means that multiple consonants may be soft despite their underlyingly (and orthographically) being hard. The process of voicing assimilation applies across word-boundaries when there is no pause between words. Within a morpheme, voicing is not distinctive before obstruents (except for, and when followed by a vowel or sonorant). The voicing or devoicing is determined by that of the final obstruent in the sequence: просьба ('request'), водка  ('vodka'). In foreign borrowings, this isn't always the case for, as in Адольф Гитлер ('Adolf Hitler') and граф болеет ('the count is ill'). and are unusual in that they seem transparent to voicing assimilation; in the syllable onset, both voiced and voiceless consonants may appear before :
 * тварь ) ('the creature')
 * два ('two')
 * световой ('of light')
 * звезда ('star')

When precedes and follows obstruents, the voicing of the cluster is governed by that of the final segment (per the rule above) so that voiceless obstruents that precede  are voiced if  is followed by a voiced obstruent (e.g. к вдове  'to the widow') while a voiceless obstruent will devoice all segments (e.g. без впуска  'without an admission').

,, and have voiced allophones (,  and ) before voiced obstruents, as in дочь бы  ('a daughter would') and плацдарм  ('bridge-head').

Other than and, nasals and liquids devoice between voiceless consonants or a voiceless consonant and a pause: контрфорс ) ('buttress').

Palatalization
Before, paired consonants are normally soft as in пью 'I drink' and пьеса  'theatrical play'. However the last consonant of prefixes and parts of compound words generally remains hard in the standard language: отъезд 'departure', Минюст  'Min[istry of] Just[ice]'; and only when prefix ends in  or, there exists an optional softening: съездить  ('to travel').

Paired consonants preceding are also soft; although there are exceptions from loanwords, alternations across morpheme boundaries are the norm. The following examples show some of the morphological alternations between a hard consonant and its soft pair:
 * дом 'house' nominative) vs. до́ме  'house' prepositional)
 * крова́вый 'bloody' vs. крова́веть  'to become bloody'
 * отве́т 'answer' vs. отве́тить  'to answer'
 * (я) несу́ '(I) carry' vs. (он, она, оно) несёт  'carries'
 * жена́ 'wife' vs. же́нин  'wife's'
 * коро́ва 'cow' vs. коро́вий  'bovine'
 * прям '(is) straight' vs. прямизна́  'straightness'
 * вор ('thief') vs. вори́шка  'little thief (pejorative)'
 * написа́л 'he wrote' vs. написа́ли  'they wrote'
 * горбу́н 'hunchback' vs. горбу́нья  'female hunchback'
 * высо́к '(is) high' vs. высь  'height'

Velar consonants are soft when preceding ; within words, this means that velar consonants are never followed by.

Before hard dental consonants,, labial and dental consonants are hard: орла ('eagle' gen. sg).

Assimilative palatalization
Paired consonants preceding another consonant often inherit softness from it. This phenomenon in literary language has complicated and evolving rules with many exceptions, depending on what these consonants are, in what morphemic position they meet and to what style of speech the word belongs. In old Moscow pronunciation, softening was more widespread and regular; nowadays some cases that were once normative have become low colloquial or archaic. In fact, consonants can be softened to very different extent, become semi-hard or semi-soft.

The more similar the consonants are, the more they tend to soften each other. Also, some consonants tend to be softened less, such as labials and.

Softening is stronger inside the word root and between root and suffix; it is weaker between prefix and root and weak or absent between a preposition and the word following.


 * Before soft dental consonants, and often soft labial consonants, dental consonants (other than ) are soft.


 * is assimilated to the palatalization of the following velar consonant: лёгких ) ('lungs' gen. pl.).


 * Palatalization assimilation of labial consonants before labial consonants is in free variation with nonassimilation, that is бомбить ('to bomb') is either or  depending on the individual speaker.


 * When hard precedes its soft equivalent, it is also soft and likely to form a single long sound (see gemination). This is slightly less common across affix boundaries.

In addition to this, dental fricatives conform to the place of articulation (not just the palatalization) of following postalveolars: с частью ) ('with a part'). In careful speech, this does not occur across word boundaries.

Russian has the rare feature of nasals not typically being assimilated in place of articulation. Both and  appear before retroflex consonants: деньжонки ) ('money' (scornful)) and ханжой ) ('sanctimonious one' instr.). In the same context, other coronal consonants are always hard. A partial exception to this is the velar nasal, which occurs as an allophone before velar consonants in some words (функция ) 'function'), but not in most other words like банк  ('bank').

Consonant clusters
As a Slavic language, Russian has fewer phonotactic restrictions on consonants than many other languages, allowing for clusters that would be difficult for English speakers; this is especially so at the beginning of a syllable, where Russian speakers make no sonority distinctions between fricatives and stops. These reduced restrictions begin at the morphological level; outside of two morphemes that contain clusters of four consonants: встрет-/встреч- 'meet', and чёрств-/черств- 'stale' , native Russian morphemes have a maximum consonant cluster size of three:

For speakers who pronounce instead of, words like общий ('common') also constitute clusters of this type.

If is considered a consonant in the coda position, then words like айва ('quince') contain semivowel+consonant clusters.

Affixation also creates consonant clusters. Some prefixes, the best known being вз-/вс-, produce long word-initial clusters when they attach to a morpheme beginning with multiple consonants (e.g. ||+ || → взблеск  'flash'). However, the four-consonant limitation persists in the syllable onset.

Clusters of three or more consonants are frequently simplified, usually through syncope of one of them, especially in casual pronunciation.

All word-initial four-consonant clusters begin with or, followed by a stop (or, in the case of , a fricative), and a liquid:

Because prepositions in Russian act like clitics, the syntactic phrase composed of a preposition (most notably, the three that consist of just a single consonant: к, с, and в) and a following word constitutes a phonological word that acts like a single grammatical word. For example, the phrase с друзья́ми ('with friends') is pronounced. In the syllable coda, suffixes that contain no vowels may increase the final consonant cluster of a syllable (e.g. Ноябрьск 'city of Noyabrsk' ||+ || → ), theoretically up to seven consonants: *монстрств  ('of monsterships'). There is usually an audible release between these consecutive consonants at word boundaries, the major exception being clusters of homorganic consonants.

Consonant cluster simplification in Russian includes degemination, syncope, dissimilation, and weak vowel insertion. For example, is pronounced, as in расщелина ('cleft'). There are also a few isolated patterns of apparent cluster reduction (as evidenced by the mismatch between pronunciation and orthography) arguably the result of historical simplifications. For example, dental stops are dropped between a dental continuant and a dental nasal or lateral: лестный 'flattering'. Other examples include:
 * > : чувство 'feeling', not.
 * > : солнце 'sun' ), not.
 * > : сердце 'heart', not.
 * > : сердчишко 'heart (diminutive)', not.
 * > : шотландский ('Scottish') ) not.
 * > : марксистский ('Marxist') not.

The simplifications of consonant clusters are done selectively; bookish-style words and proper nouns are typically pronounced with all consonants even if they fit the pattern. For example, the word голландка is pronounced in a simplified manner for the meaning of 'Dutch oven' (a popular type of oven in Russia) and in a full form  for 'Dutch woman' (a more exotic meaning).

In certain cases, this syncope produces homophones, e.g. костный ('bony') and косный ('rigid'), both are pronounced.

Another method of dealing with consonant clusters is inserting an epenthetic vowel (both in spelling and in pronunciation), $\langleхг\rangle$, after most prepositions and prefixes that normally end in a consonant. This includes both historically motivated usage and cases of its modern extrapolations. There are no strict limits when the epenthetic $\langleг\rangle$ is obligatory, optional, or prohibited. One of the most typical cases of the epenthetic $⟨о⟩$ is between a morpheme-final consonant and a cluster starting with the same or similar consonant (e.g. со среды 'from Wednesday' ||+ || →, not *с среды; ототру 'I'll scrub' ||+  || → , not *оттру).

Supplementary notes
There are numerous ways in which Russian spelling does not match pronunciation. The historical transformation of into  in genitive case endings and the word for 'him' is not reflected in the modern Russian orthography: the pronoun его  'his/him', and the adjectival declension suffixes -ого and -его. Orthographic г represents in a handful of word roots: легк-/лёгк-/легч- 'easy' and мягк-/мягч- 'soft'. There are a handful of words in which consonants which have long since ceased to be pronounced even in careful pronunciation are still spelled, e.g., the 'l' in солнце ('sun').

and are the only consonants that can be geminated within morpheme boundaries. Such gemination does not occur in loanwords.

Between any vowel and (excluding instances across affix boundaries but including unstressed vowels that have merged with ),  may be dropped: аист  ('stork') and делает  ('does'). ( cites заезжать and other instances of intervening prefix and preposition boundaries as exceptions to this tendency.)

Stress in Russian may fall on any syllable and words can contrast based just on stress (e.g. мука 'ordeal, pain, anguish' vs.  'flour, meal, farina'); stress shifts can even occur within an inflexional paradigm: до́ма  ('house' gen. sg.) vs дома́  ('houses'). The place of the stress in a word is determined by the interplay between the morphemes it contains, as some morphemes have underlying stress, while others do not. However, other than some compound words, such as морозоустойчивый ('frost-resistant') only one syllable is stressed in a word.

velarizes hard consonants: ты ('you' sing.). and velarize and labialize hard consonants and labialize soft consonants: бок  ('side'), нёс  ('(he) carried').

Between a hard consonant and, a slight offglide occurs, most noticeably after labial, labio-dental and velar consonants (e.g. мок, 'side' ). Similarly, a weak palatal offglide may occur between certain soft consonants and back vowels (e.g. ляжка 'thigh' ).

Historical sound changes
The modern phonological system of Russian is inherited from Common Slavonic, but underwent considerable innovation in the early historical period, before being largely settled by about 1400.

Like all Slavic languages, Old Russian was a language of open syllables. All syllables ended in vowels, and consonant clusters, in far lesser variety than today, existed only in the syllable onset. However, by the time of the earliest records, Old Russian already showed characteristic divergences from Common Slavonic.

Around the tenth century, Russian may have already had paired coronal fricatives and sonorants so that could have contrasted with, though any possible contrasts were limited to specific environments. Otherwise, palatalized consonants appeared allophonically before front vowels. When the yers were lost, the palatalization initially triggered by high vowels remained, creating minimal pairs like данъ ('given') and дань  ('tribute'). At the same time,, which was already a part of the vocalic system, was reanalyzed as an allophone of after hard consonants, prompting leveling that caused vowels to alternate according to the preceding consonant rather than vice versa.

The nasal vowels (spelled in the Cyrillic alphabet with yuses), which had developed from Common Slavic *eN and *oN before a consonant, were replaced with nonnasalized vowels, possibly iotated or with softening of the preceding consonant:
 * PIE: *h₁sónti
 * Latin: sunt
 * Common Slavonic:
 * Old Church Slavonic:
 * Russian: суть ('they are', bookish 3rd person pl form of быть 'to be', cf. Polish są).

Borrowings in the Uralic languages with interpolated after Common Slavonic nasal vowels have been taken to indicate that the nasal vowels did exist in East Slavic until some time possibly just before the historical period.

Simplification of Common Slavic *dl and *tl to *l:
 * Common Slavonic:
 * Polish: mydło
 * Russian: мыло ('soap').

A tendency for greater maintenance of intermediate ancient, , etc. before frontal vowels, than in other Slavic languages, the so-called incomplete second and third palatalizations:
 * Ukrainian нозі
 * Russian: ноге ('leg' dat.).

Pleophony or "full-voicing" (polnoglasie, 'полногласие' ), that is, the addition of vowels on either side of and  between two consonants. Church Slavonic influence has made it less common in Russian than in modern Ukrainian and Belarusian:
 * Old Church Slavonic: vrabii
 * Russian: воробей ('sparrow')


 * Ukrainian: Володимир
 * Russian: Владимир ('Vladimir') (although the nickname form in Russian is still Володя ).

Major phonological processes in the last thousand years have included the absence of the Slavonic open-syllable requirement, achieved in part through the loss of the ultra-short vowels, the so-called fall of the yers, which alternately lengthened and dropped (the yers are given conventional transcription rather than precise IPA symbols in the Old Russian pronunciations):
 * Old East Slavic:  &gt; R: обо мне  ('about me')
 * OR: сънъ &gt; R: сон  ('sleep' nom. sg.), cognate with Lat. somnus;
 * OR: съна &gt; R: сна  ('of sleep') (gen. sg.).

The loss of the yers has led to geminated consonants and a much greater variety of consonant clusters, with attendant voicing and/or devoicing in the assimilation:


 * OR:  &gt; R: где  ('where').

Consonant clusters thus created were often simplified:
 * здравствуйте ('hello'), (first 'v' rarely pronounced; such a pronunciation could be affected in the archaic meaning be healthy)
 * сердце ('heart') ('d' not pronounced)
 * солнце ('sun') ('l' not pronounced).

The development of OR  (conventional transcription) into, as seen above. This development has caused by far the greatest of all Russian spelling controversies. The timeline of the development of into  or  has also been debated.

Sometime between the twelfth and fourteenth century, the allophone of before velar consonants changed from  to  with subsequent palatalization of the velars.

The retroflexing of postalveolars: became  and  become. This is considered a "hardening" since retroflex sounds are difficult to palatalize. At some point, resisted palatalization, which is why it is also "hard" although phonetically it is no different from before. The sound represented by $⟨о⟩$ was much more commonly pronounced than it is today. Today's common and standard pronunciation of $⟨о⟩$ is.

The development of stressed into  when between a (historically) soft consonant and a hard one. This has led to a number of alternations:
 * OR о чемъ ('about which' loc. sg.) &gt; R о чём.

Note that the that derives from the long obsolete vowel, yat  did not undergo this change except for a short list of words as of about a century ago. Nowadays, the change has been reverted in two of those exceptional words.
 * вдёжка 'threading needle, bodkin'
 * гнёзда 'nests'
 * желёзка 'glandule' (however желе́зка 'piece of iron')
 * запечатлён '[he/it is] depicted; [he/it is] imprinted (in the mind)'
 * звёзды 'stars'
 * зёвывал '[he] used to yawn'
 * издёвка 'jibe'
 * (ни разу не) надёван '[it is] (never) worn'
 * обрёл '[he] found'
 * сёдла 'saddles'
 * смётка 'apprehension'
 * цвёл '[he] flowered, flourished'
 * надёвывал '[he] used to put on' (this word has fallen into disuse in the standard language)
 * подгнёта 'fuel, chips; instigation; firebrand' (this word has fallen into disuse in the standard language)
 * вёшка 'way-mark' (now ве́шка)
 * медвёдка 'mole cricket', 'mole rat' (now медве́дка)

Loanwords from Church Slavonic reintroduced between a (historically) soft consonant and a hard one, creating a few new minimal pairs:
 * не́бо 'sky' vs. нёбо 'roof of the mouth'
 * паде́ж 'case (grammatical)' vs. падёж 'murrain, epizooty'
 * вселе́нная 'universe' vs. вселённая 'settled' (f.)
 * соверше́нный 'perfect' vs. совершённый 'completed, committed, performed, achieved'

A number of the phonological features of Russian are attributable to the introduction of loanwords (especially from non-Slavic languages), including:
 * Sequences of two vowels within a morpheme. Only a handful of such words, like паук 'spider' and оплеуха 'slap in the face' are native.
 * поэт 'poet'.  From French poète.
 * траур 'mourning'. From German Trauer.
 * Word-initial, except for the root эт-.
 * эра 'era'.  From German Ära
 * Word-initial.
 * авеню 'avenue. From French avenue.
 * афера 'swindle'. From French affaire.
 * агнец 'lamb'. From Church Slavonic
 * The phoneme (see Ef (Cyrillic) for more information).
 * фонема 'phoneme'.  From Greek φώνημα.
 * эфир 'ether'. From Greek αἰθήρ.
 * фиаско 'fiasco. From Italian fiasco.
 * The occurrence of non-palatalized consonants before within roots. (The initial  of a suffix or flexion invariably triggers palatalization of an immediately preceding consonant, as in брат / братец / о брате.)
 * The sequence within a morpheme.
 * джин ) 'gin' from English.
 * джаз 'jazz' from English.

Many double consonants have become degeminated, though they are still written with two letters in the orthography. (In a 1968 study, long remains long in only half of the words that it appears written in, while long  only a sixth of the time. The study, however, did not distinguish spelling from actual historical pronunciation, since it included loanwords in which consonants were written doubled but never pronounced long in Russian.)