Russian spelling is reasonably phonemic in practice. It is in fact a balance among phonemics, morphology, etymology, and grammar; and, like that of most living languages, has its share of inconsistencies and controversial points. A number of rigid spelling rules introduced between the 1880s and 1910s have been responsible for the former whilst trying to eliminate the latter.
The current spelling follows the major reform of 1918, and the final codification of 1956. An update proposed in the late 1990s has met a hostile reception, and has not been formally adopted. The punctuation, originally based on Byzantine Greek, was in the 17th and 18th centuries reformulated on the French and German models.
According to the Institute of Russian Language of the Russian Academy of Sciences, an optional acute accent (знак ударения) may, and sometimes should, be used to mark stress. For example, it is used to distinguish between otherwise identical words, especially when context does not make it obvious: замо́к/за́мок (lock/castle), сто́ящий/стоя́щий (worthwhile/standing), чудно́/чу́дно (this is odd/this is marvelous), молоде́ц/мо́лодец (attaboy/fine young man), узна́ю/узнаю́ (I shall learn it/I am recognizing it), отреза́ть/отре́зать (to cut/to have cut); to indicate the proper pronunciation of uncommon words, especially personal and family names (афе́ра, гу́ру, Гарси́я, Оле́ша, Фе́рми), and to express the stressed word in the sentence (Ты́ съел печенье?/Ты съе́л печенье?/Ты съел пече́нье? – Was it you who ate the cookie?/Did you eat the cookie?/Was it the cookie that you ate?). Stress marks are mandatory in lexical dictionaries and books for children or Russian learners.
As a historical aside, Vladimir Dal was, in the second half of the 19th century, still insisting that the proper spelling of the adjective русский, which was at that time applied uniformly to all the Orthodox Eastern Slavic subjects of the Empire, as well as to its one official language, should be <руский> with one <с>, in accordance with ancient tradition and what he termed the “spirit of the language”. He was contradicted by the philologist Yakov Grot, who distinctly heard the <с> lengthened or doubled.