Moscow dialect

The Moscow dialect or Moscow accent (Московское произношение), sometimes Central Russian, is the spoken Russian language variety used in Moscow – one of the two major pronunciation norms of the Russian language alongside the Saint Petersburg norm. Influenced by both Northern and Southern Russian dialects, the Moscow dialect is the basis of the Russian literary language.

Overview
The 1911 edition of the Encyclopædia Britannica wrote:

"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 о"

- o as а