[4] The 1911 edition of the Encyclopædia Britannica wrote:[5] Literary Russian as spoken by educated people throughout the empire is the Moscow dialect...
The Moscow dialect really covers a very small area, not even the whole of the government of Moscow, but political causes have made it the language of the governing classes and hence of literature.
It is a border dialect, having the southern pronunciation of unaccented o as a, but in the jo for accented e before a hard consonant it is akin to the North and it has also kept the northern pronunciation of g instead of the southern h. So too unaccented e sounds like i or ji.
In the 15th century, the Moscow dialect was similar to the northern Russian dialects in its phonological system, except that, unlike now, it was not characterized by the ts–ch merger peculiar to Novgorod Russian.
[7] The changes in the system of sounds in Russian during the Moscow period (15th to 17th centuries) primarily include the spread of akanye, as well as the preservation of certain pronunciations of 'e' before hard consonants in the 'ecclesiastical style', the complete merging of 'е' and 'ѣ', and the sporadic use of [ɣ] for [ɡ] in a small number of words.