Most speakers, particularly among the Zaza, Dimli, Gorani and Shabaki, consider themselves to be ethnic Kurds, though their languages are not classified as Kurdish.
The area of the Northwestern Iranian languages was largely overrun by Turkic languages, subsequently known as Azeri or Azerbaijani, introduced in the 11th century. By the 16th century, this language had ousted the indigenous Iranian languages except from the peripheral area along the Caspian coast. Two of these northwestern dialects, however, survive outside the area; they are Zaza and Gorani. The Gorani moved south, but their language, now much declined, survives only in the neighbourhood of Kermanshah.
As the language of the Ahl-e Haqq, Gorani became the vehicle of a considerable literature. The Zazas, living adjacent to the Kurds of Eastern Turkey and often considered Kurds themselves, are thought by some to be descended from immigrants from Dailam on the southern shore of the Caspian. They retain the language of their ancestors, speakers of the southern dialect of which call their language Dimli.