To the far north of Kurdistan along the upper courses of the Euphrates, Kizilirmaq, and Murat rivers in Turkey, the Dimilí branch of Kurdish language (less accurately but more commonly known as Zâza) is spoken by about 4.5 million (data from late 80's) Dimilí Kurds, (See the map). The larger cities of Darsim (now Tunçeli), Chapakhchur (now Bingol), and Siverek, and a large proportion of the Kurds of Bitlis, are Dimilí-speaking. There are also smaller pockets of this language spoken in various corners of Anatolia from Adiysman to Malatya (Melatye) and Maras (Meres), in Southern Kurdistan (northern Iraq, where the speakers are known as the Shebeks) and North Esatern Kurdistan (northwest Iran, the tribes of Dumbuli and some of the Zerzas) as well. The language seems in late classical and early medieval times to have been more or less spoken in all the area now covered by Northern Kurdish Dilects group in contiguous Kurdistan. Its domain also stretched west into Pontus, Cappadocia, and Cilicia, before a sustained period of assimilation and deportations obliterated the Kurdish presence in the area in the Byzantine period. The Dimilí further retreated from its former eastern domains to its present limited one under pressure from the advancing Northern Kurdish Dilects group speaking pastoralist Kurds. This loss of ground, which started at the beginning of the 16th century, continues to this day.
Dimilí is closely related to Hewramí (Hawramani, Ewramani), a relationship indicative of a time when a single form of Pahlawâni was spoken throughout much of Kurdistan, when after the late classical period, Kurdistan was homogenized through massive internal migrations. At that time the domain of the Pahlawâni language was uninterrupted across Kurdistan. The main bodies of Dimilí- and Hewramí-speaking Kurds are now at the extreme opposite ends of Kurdistan.
Major dialects of Dimilí are Sívirikí, Korí, Hezzú (or Hezo), Motkí (or Motí), and Dumbulí. The dialect of Galishí now spoken in the highlands of Gilan on the Caspian Sea may be a distant offshoot of Dimilí as well, brought here by the migrating medieval Daylamites from western and northern Kurdistan.
Dimilí has served as the prime language of the sacred scriptures of the Alevis, but not the exclusive one. Despite this, not much written material survives to give an indication of the older forms of Dimilí and its evolution. The documents come from rather unexpected sources: the early medieval Islamic histories. Ibn Isfandiyar in his history of Tabaristan, for example, preserves passages in the language of the Daylamite settlers of this Caspian Sea district, which resembles modern Dimilí.