 In 1939, the Nanai spelling rules in Cyrillic were adopted, refined in 1958, when the Nanai alphabet began to contain all 33 letters of the Russian alphabet, as well as the letter Ӈ ӈ (instead of "Нг нг").However, in fact, in most publications, instead of "Ӈ ӈ", the use of "Нг нг" continued.The current version of the Nanai alphabet was approved in 1993.