North Azerbaijani has official status in the Republic of Azerbaijan and Dagestan (a federal subject of Russia) but South Azerbaijani does not have official status in Iran, where the majority of Azerbaijanis live. It is also spoken to lesser varying degrees in Azerbaijani communities of Georgia and Turkey and by diaspora communities, primarily in Europe and North America.
Both North Azerbaijani and South Azerbaijani are members of the Oghuz branch of the Turkic languages. North Azerbaijani (spoken in the Republic of Azerbaijan and Russia) is based on the Shirvani dialect and South Azerbaijani (spoken in Iran) is based on the Tabrizi dialect, and is closely related to Turkish, Qashqai, Gagauz, Turkmen and Crimean Tatar, sharing varying degrees of mutual intelligibility with each of those languages.
Historically the language was referred to locally as Türki meaning "Turkic" or Azərbaycan Türkcəsi meaning "Azerbaijani Turkish" and scholars such as Vladimir Minorsky used this definition in their works, distinguishing it from İstanbul Türkçesi ("Istanbul Turkish"), the official language of Turkey. Modern literature in the Republic of Azerbaijan is based on the Shirvani dialect mainly, while in Iranian Azerbaijan region (historic Azerbaijan) it is based on the Tabrizi one.