Russian spelling rules
In Russian, the term spelling rule is used to describe a number of rules relating to the spelling of words in the language that would appear in most cases to deviate from a strictly phonetic transcription. All the spelling rules found in the Russian language dictate that certain consonants "cannot" be followed either "under any circumstance" or in an "unstressed syllable" by certain vowels. In most cases where spelling rules exist, they do not actually affect the pronunciation. This is a result of the fact that five of the eight Russian consonants for which spelling rules  of one sort or another apply can only be either "hard" "or" "soft" and cannot be both. Only with the three velar consonants, which like most Russian consonants have both a hard and a soft form, does the spelling rule actually reflect phonetically based pronunciation. Spelling rules are of major importance in the study of Russian morphology. They have a very considerable effect on the declension of nouns and adjectives and the conjugation of verbs because many of the endings produce consonant-vowel combinations that the spelling rules strictly forbid. In some cases where stress dictates whether or not  a spelling rule is to be applied, "mixed declensions" can result. Russian grammar goes so far as to dictate that the spelling rules must take precedence over any other rule.