Russian Spelling Rules
There are 3 vocalic-based spelling rules in Russian. These rules demonstrate which combinations of letters are not permitted in Russian. It should be noticed that these spelling rules explain many of the irregularities in the declension of Russian nouns, pronouns and adjectives, and in the conjugation of Russian verbs.
Spelling rule №1
The letter ы may not occur after г, к, х and ж, ч, ш, щ. Instead of ы, the letter и should be written. This rule is particularily important for plural forms of nouns and in endings of adjectives.
Spelling rule №2
The letters ю and я may not occur after г, к, х and ж, ц, ч, ш, щ. Instead of ю and я, the letters у and а should be written, respectively. This rule is particularily important in verb endings.
Spelling rule №3
Unstressed о may not occur after ж, ц, ч, ш, щ in endings (but it may occur in roots). The letter о should be replaced by the letter е.