Except for a brief period after
World War II, the use of ⟨ё⟩ was never obligatory in standard Russian orthography. By and large, it is used only in dictionaries and in pedagogical literature intended for children and students of Russian as a second language. Otherwise, ⟨е⟩ is used, and ⟨ё⟩ occurs only when it is necessary to avoid ambiguity (such as to distinguish between все ("everybody") and всё ("everything") when it is not obvious from the context) or in words (principally proper nouns) whose pronunciation may not be familiar to the reader. Recent recommendations (2006) from the
Russian Language Institute are to use ⟨ё⟩ in proper nouns to avoid an incorrect pronunciation.
[7] It is permitted, however, to mark ⟨ё⟩ whenever it occurs,
[7] which is the preference of some Russian authors and periodicals.
The fact that ⟨ё⟩ is frequently replaced with ⟨е⟩ in print often causes some confusion to both Russians and non-Russians, as it makes it more difficult for Russian words and names to be transcribed. One recurring problem is with Russian surnames, as both -ев (
-ev/-yev) and -ёв (
-yov/-ov) are common endings. Thus, the English-speaking world knows two leaders of the former
Soviet Union as
Khrushchev and
Gorbachev, but their surnames end in Russian with -ёв, better transcribed
-yov/-ov (which is why many English-speakers
pronounce these names as if they end in -ov but they
spell them with -ev).
...
It is thought that the letter ⟨ё⟩ is found in at least 2500 surnames used in Russia and other states of the former USSR. It is common for a person who has one of these surnames to possess some legal documents (passports, identification cards, marriage and birth certificates, property ownership papers, etc.) where the name is written with a ⟨ё⟩, and some that use the simple ⟨е⟩ instead. In other situations, a child's birth certificate may have a ⟨ё⟩ and the parents' identity papers all have ⟨е⟩. On occasion such mismatches caused problems to citizens who receive inheritance or complete property transactions