The Eigə-Isthmus languages are a family of related languages spoken in eastern Peilaš. Their last common ancestor, Proto-Eigə-Isthmus, was probably spoken in the region that later became Huyfárah between about -5000 and -4500 YP. Comparative and reconstructive work on the family is ongoing.
Known members of the family include:
- Proto-Eigə-Isthmus (Huyfárah, c. -5000 to -4500 YP)
- Eigə Valley languages
- Isthmus languages: Proto-Isthmus (Huyfárah, c. -3000 YP)
- Western Isthmus languages
- Eastern Isthmus languages
- Doroh (Doroh, c. 500 YP)
- Kennan (northern Siixtaguna, c. 500 YP)
- Kietek (western Siixtaguna, c. 500 YP)
- Ka'alikora (western Siixtaguna, c. 500 YP)
Ngauro was the first written language in this part of the world (at least); it's attested from the late fourth millennium to the mid second millennium BP, with inscriptions found mainly in Kasca and nearby regions.
The closely related Miwan languages are spoken in the southern Aiwa valley; the best known are those spoken on the southern fringes of Kasca (Eastern Miwan) and in the Etewg Peidæm or Ici Forest (Forest Miwan) during the first millennium YP.
Meshi is another closely related language, originally spoken in the middle and upper Aiwa regions; at the beginning of the first millennium BP, Meshi-speaking nomads conquered most of the valley, leaving inscriptions scattered throughout their large (but short-lived) empire. The exact relationship of Meshi to Ngauro and Miwan is disputed; some scholars place it within the Miwan group, while others make it a third branch of the Eigə Valley family.
The Isthmus languages are a diverse group, spoken mainly north and east of Huyfárah. The best known of these is the Western Isthmus language Faraghin, spoken in the late 2nd millennium BP in northern Huyfárah, which had a major influence on the development of Fáralo; also important is the Eastern Isthmus language Doroh, spoken in the first millennium YP in the region east of Huyfárah.