Akanye or akanje^[1] (Belarusian: аканне, Russian: а́канье, Russian pronunciation: [ˈakənʲjɪ]), literally "a-ing", is a sound change in Slavic languages in which the phonemes /o/ or /e/ are realized as more or less close to [a]. It is a case of vowel reduction.

The most familiar example is probably Russian akanye (pronounced but not represented orthographically in the standard language). Akanye also occurs in:

• Standard Belarusian (represented orthographically)
• Northern (Polissian) Ukrainian dialects
• Slovene dialects (e.g., Lower Carniolan dialects),^[2]
• Some subgroups of the Kajkavian dialect of Serbo-Croatian^[3]
• Bulgarian dialects (e.g., the Rhodope dialects, including the Smolyan dialect).^[4]

In Belarusian аканне (akanne), both non-softened and softened /o/ and /a/ and other phonemes phonetically merge into [a] in unstressed positions; see Belarusian phonology.

In Russian а́канье (akan'ye), (except for Northern dialects), /o/ and /a/ phonetically merge in unstressed positions. If not preceded by a palatalized (soft) consonant, these phonemes give [ɐ] (sometimes also transcribed as [ʌ]) in the syllable immediately before the stress^[5] and in absolute word-initial position.^[6] In other unstressed locations, non-softened /o/ and /a/ are further reduced towards a short, poorly enunciated [ə].^[7] The phonemic dialectal feature of clear distinction of the unstressed o (i.e., no reduction) is called okanye [ru] (Russian: о́канье), literally "o-ing".

After soft consonants, unstressed /o/ and /a/ are pronounced like [ɪ] in most varieties of Russian (see vowel reduction in Russian for details); this reduction is not considered a manifestation of akanye. Unlike Belarusian akanne, Russian akanye does not affect softened vowels.

Slovene akanje may be partial (affecting only syllables before or after the stressed vowel) or complete (affecting all vowels in a word).^[2] Examples from various Slovene dialects: domú → damú 'at home' (pretonic o),^[2] dnò → dnà 'bottom' (tonic o),^[8] léto → líəta (posttonic o),^[8] ne vém → na vém 'I don't know' (pretonic e),^[2] hléb → hlàb 'loaf' (tonic e),^[8] jêčmen → jèčman 'barley' (posttonic e).^[8]

• Vowel reduction in Russian – about ikanye.