The Russian insular dialect of Azerbaijan goes back to the dialects that from the very beginning of their existence were in close Azerbaijan environment. One of the phonetic features of the insular dialect is progressive assimilative softening of back palatal consonants which refers to relict phenomena and persists (despite the emerging trend of leveling the dialect) due to the bilingualism of Russian settlers, their assimilation of the non-equivalent Azerbaijani vowel /ә/, reflects the manifestation of "Turkic synharmonism" and is supported by currently leveling yakanye.