The most significant instance of this is found in the representation of vowel reduction, and in particular akanje, the merger of unstressed /a/ and /o/, which exists in both Russian and Belarusian. Belarusian always spells this merged sound as , whereas Russian uses either or , according to what the "underlying" phoneme is (determined by identifying the related words where the vowel is being stressed or, if no such words exist, by written tradition, mostly but not always conforming to etymology). This means that Belarusian noun and verb paradigms, in their written form, have numerous instances of alternations between written and , whereas no such alternations exist in the corresponding written paradigms in Russian. This can significantly complicate the foreign speakers' task of learning these paradigms; on the other hand, though, it makes spelling easier for native speakers.
The most significant instance of this is found in the representation of vowel reduction, and in particular akanje, the merger of unstressed /a/ and /o/ which exists in both Russian and Belarusian. Belarusian always spells this merged sound as , whereas Russian uses either or , according to what the "underlying" phoneme is (determined by identifying the related words where the vo,wel is being stressed or, if no such words exist, by written tradition, mostly but not always conforming to etymology). This means that Belarusian noun and verb paradigms, in their written form, have numerous instances of alternations between written and , whereas no such alternations exist in the corresponding written paradigms in Russian. This can significantly complicate the foreign speakers' task of learning these paradigms; on the other hand, though, it makes spelling easier for native speakers.