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 not absolute agreement on the number of phonemes, so that rarer or contextually variant sounds are included by some scholars.
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 ⟨?⟩). 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.
Unlike in Russian, Belarusian spelling closely represents surface phonology rather than the underlying morphophonology. For example, akannye, tsyekannye, dzyekannye and the [w] allophone of /v/ and /l/ are all written. The representation of akannye in particular introduces striking differences between Russian and Belarusian orthography.[example needed]
|Belarusian Cyrillic script||Belarusian Latin script||IPA||Description||Belarusian example|
|i||i||/i/||close front unrounded||?i ('leaf')|
|?||?||/?/||mid-central (unstressed), open-mid front unrounded (stressed)||?? ('this one')|
|e||?, ie, je||[?e?]||Palatalises preceding consonant followed by mid front unrounded vowel||[example needed]|
|?||y||[?]||close central unrounded||??? ('mouse')|
|a, ?||a||/a/||open central unrounded||??? ('executioner')|
|?, ?||u||/u/||close back rounded||??? ('noise')|
|?, ?||o||/o/ [?]||open-mid back rounded||??? ('cat')|
As with Russian, [?] is not a separate phoneme, but an allophone of /i/ occurring after non-palatalized consonants.
The consonants of Belarusian are as follows:
This section needs expansion with: consonant allophonies. You can help by adding to it. (December 2018)
The rare phonemes /?/ and // are present only in several borrowed words: ['?anak], ['?uzik]. Other borrowed words have the fricative pronunciation: [ea'?raf?ija] ('geography'). In addition, [?] and  are allophones of /k/ and /k?/ respectively, when voiced by regressive assimilation, as in [va?'zal] 'train station'.
In the syllable coda, /v/ is pronounced [w] or [u?], forming diphthongs, and is spelled ⟨?⟩.[w] sometimes derives etymologically from /l/, as with ? [v?wk] ('wolf'), which comes from Proto-Slavic *v?lk?. Similar to Ukrainian, there are also alternations between /w/ and /l/ in the past tense of verbs: for example, /'dumaw/ "(he) thought" versus ? /'dumala/ "(she) thought". This evolved historically from a spelling with -? () which vocalized like the ? in Polish (cognate duma?, "he mused").
The geminated variations are transcribed as follows: