The phonological system of the modern Belarusian language consists of at least 44 phonemes: 5 vowels and 39 consonants. Consonants may also be geminated. There is no absolute agreement on the number of phonemes; rarer or contextually variant sounds are included by some scholars.^{[citation needed]}

Many consonants may form pairs that differ only in palatalization (called hard vs soft consonants, the latter being represented in the IPA with the symbol ⟨ʲ⟩). In some of such pairs, the place of articulation is additionally changed (see distinctive features below). There are also unpaired consonants that have no corollary in palatalization.

Distinctive features

As an East Slavic language, Belarusian phonology is very similar to both Russian and Ukrainian phonology. The primary differences are:^[1]

• Akannye (Belarusian: аканне) – the merger of unstressed /o/ into /a/. The pronunciation of the merged vowel is a clear open front unrounded vowel [a], including after soft consonants and /j/. In standard Russian akanye, the merger happens only after hard consonants; after soft consonants, /o/ merges with /i/ instead. Ukrainian does not have this merger at all. In Belarusian, unlike Russian, this change is reflected in spelling: compare галава́ "head", pronounced [ɣalaˈva]^ⓘ, with Russian голова́ [ɡəlɐˈva]^ⓘ and Ukrainian голова́ [ɦɔlɔˈwɑ]^ⓘ.
• Lack of ikanye (the Russian sound change in which unstressed /e/ has merged with /i/, and unstressed /a/ and /o/ with /i/ after soft consonants). Instead, unstressed /e/ merges with /a/ (yakannye). Compare Belarusian зямля́ [zʲamˈlʲa]^ⓘ with Russian земля́ [zʲɪˈmlʲa]^ⓘ and Ukrainian [zeˈmlʲɑ]^ⓘ.
  Not all instances of */e/ are subject to yakannye in literary Belarusian, for example па́лец [ˈpalʲɛts]^ⓘ instead of па́ляц [ˈpalʲats], which occurs only dialectally. In standard Belarusian, yakannye after palatalized consonants occurs in the syllable immediately preceding the tonic syllable: пе́сня [ˈpʲɛsʲnʲa] "song" — пясня́р [pʲasʲˈnʲar] "singer" — песняры́ [pʲɛsʲnʲaˈrɨ] "singers". Exceptions are allowed in loanwords: меда́ль [mʲɛˈdalʲ] "medal".
• Tsyekannye (Belarusian: цеканне) and dzyekannye (Belarusian: дзеканне) – the pronunciation of Old East Slavic /tʲ, dʲ/ as soft affricates [tsʲ, dzʲ]. This occurs in дзе́сяць "ten", pronounced [ˈdzʲɛsʲatsʲ]; compare Russian де́сять [ˈdʲesʲɪtʲ]^ⓘ, Ukrainian де́сять [ˈdɛsʲɐtʲ]^ⓘ.
  Many Russian speakers similarly affricate phonemic /tʲ, dʲ/, but this is not universal and not written.
• Relatively stronger palatalization of /sʲ/ and /zʲ/.^[2]
• Postalveolar consonants are all hard (laminal retroflex), whereas Russian has both hard and soft postalveolars.
• /rʲ/ has hardened and merged with /r/.
• Unlike in standard Russian, historical /l/ before consonants has merged with /v/ and is pronounced [w]. This is reflected in the spelling, which uses a special symbol known as "non-syllabic u" (Belarusian: у нескладовae),^[3] written as an ⟨u⟩ with a breve diacritic on top of it: ⟨ў⟩,^? ⟨ŭ⟩.^? For example: Belarusian воўк [vowk] — Russian волк [voɫk]. The merger did not occur before suffixes (before historical ⟨ъ⟩ in the word middle): Russian and Belarusian Belarusian: палка [ˈpaɫka] "stick".
• Lenition of /ɡ/ to /ɣ/ similarly to Ukrainian, Czech, or Slovak, and unlike Russian and Polish.
• Proto-Slavic /e/ shifted to Belarusian and Russian /o/ before a hard consonant. Compare the Belarusian word for "green", зялёны [zʲaˈlʲɔnɨ], and the Russian word, зелёный [zʲɪˈlʲɵnɨj], with Ukrainian зеле́ний [zeˈlɛnɪj].

Unlike in Russian but like in Ukrainian, Belarusian spelling closely represents surface phonology rather than the underlying morphophonology. For example, akannye, tsyekannye, dzyekannye and the [w] allophone of /v/ and /l/^{[example needed]} are all written. The representation of akannye in particular introduces striking differences between Russian and Belarusian orthography.

Vowels

As with Russian, [ɨ] is not a separate phoneme, but an allophone of /i/ occurring after non-palatalized consonants.^[6]

Consonants

The consonants of Belarusian are as follows:^[7]

The rare phonemes /ɡ/ and /ɡʲ/ are present only in several borrowed words: ганак [ˈɡanak], гузік [ˈɡuzik]. Other borrowed words have the fricative pronunciation: геаграфія [ɣʲeaˈɣrafʲija] ('geography'). In addition, [ɡ] and [ɡʲ] are allophones of /k/ and /kʲ/ respectively, when voiced by regressive assimilation, as in вакзал [vaɡˈzal] 'train station'.

In the syllable coda, /v/ is pronounced [w] or [u̯], forming diphthongs, and is spelled ⟨ў⟩.^[8] [w] sometimes derives etymologically from /l/, as with воўк [vɔwk] ('wolf'), which comes from Proto-Slavic *vьlkъ. Similar to Ukrainian, there are also alternations between [w] and /l/ in the past tense of verbs:^[9] for example, ду́маў /ˈdumaw/ "(he) thought" versus ду́мала /ˈdumala/ "(she) thought". This evolved historically from a form with /l/ (as in Russian: ду́мал) which vocalized like the Ł in Polish (cognate dumał, "he mused").

The geminated variations are transcribed as follows:

• падарожжа [padaˈroʐʐa]
• ззяць [zʲzʲatsʲ]
• стагоддзе [staˈɣoddzʲe]
• каханне [kaˈxanʲnʲe]
• рассячы [rasʲsʲaˈtʂɨ]
• ліхалецце [lʲixaˈlʲettsʲe]
• сярэднявечча [sʲarɛdnʲaˈvʲettʂa].