The Alarodian family was first proposed by Fritz Hommel (1854–1936). The term comes from the name that Herodotus used to refer to the kingdom of Urartu. The connection between the Northeast and North-central families was based on claimed similarities in phonetics and grammar, such as sentence structure and an ergative case system. The Hurro-Urartian languages were included on the basis of grammatical and lexical similarities. However the genetic relationships between these languages is not clear.
K. Ostir. Beitrage zur Alarodischen Sprachwissenschaft (a monograph), I, 1921 (in German)
K. Ostir. Alarodische Sprachwissenschaft (a monograph), 1922 (in German)
A. Svanidze. "Materials for history of Alarodian tribes" (a monograph), Tbilisi, 1937 (in Russian)
G.A. Melikishvili. Questions of the oldest population of Georgia, Caucasus and the Near East (a monograph), Tbilisi, 1965 (in Georgian, Russian summary)
I. Diakonoff, S. Starostin. "Huro-Urartian as an Eastern Caucasian Language".- Munchener Studien zur Sprachwissenschaft, Baiheft, N.F., 12, 1986 (in English)
Alarodian languages.- Encyclopedia "Sakartvelo", vol. I, Tbilisi, 1997, pp. 90 (in Georgian)
Language families can be divided into smaller phylogenetic units, conventionally referred to as branches of the family, because the history of a language family is often represented as a tree diagram.
Languages are considered unclassified either because, for one reason or another, little effort has been made to compare them with other languages, or, more commonly, because they are too poorly documented to permit reliable classification.
Although deaf sign languages have emerged naturally in deaf communities alongside or among spoken languages, they are unrelated to spoken languages and have different grammatical structures at their core.