Derbent, formerly romanized as Derbend, is a city in Dagestan, Russia, located on the Caspian Sea. It is the southernmost city in Russia, and it is the second-most important city of Dagestan. Derbent occupies the narrow gateway between the Caspian Sea and the Caucasus Mountains connecting the Eurasian Steppe to the north and the Iranian Plateau to the south; covering an area of 69.63 square kilometres (26.88 sq mi), with a population of roughly 120,000 residents.

Azerbaijani or Azeri, also referred to as Azeri Turkic, is a Turkic language from the Oghuz sub-branch. It is spoken primarily by the Azerbaijani people, who live mainly in the Republic of Azerbaijan, where the North Azerbaijani variety is spoken, and in the Azerbaijan region of Iran, where the South Azerbaijani variety is spoken. North Azerbaijani has official status in the Republic of Azerbaijan and Dagestan, but South Azerbaijani does not have official status in Iran, where the majority of Azerbaijani people live. Azerbaijani is also spoken to lesser varying degrees in Azerbaijani communities of Georgia and Turkey and by diaspora communities, primarily in Europe and North America.