Argu, or theArghu languages, are a branch ofCommon Turkic languages along withOghuz,Kipchak,Karluk andSiberian Turkic. Unlike other branches, this group is not multilingual, and the historical Argu language and its descendantKhalaj are the only languages of this group.^[1][2][3]

The Arghu (اَرْغوُ), were a bilingual group of Turkic tribes in the 11th century.^[4] The first and only mention of the Argu tribes and Argu language was byAl-Kashgari. He wrote that they lived among the mountains and that is why they were called Argu, meaning "in between".^[5] In the same period (9th/10th century), the name Khalaj was also recorded by travelers. With the discovery of modern Khalajs, it is found that language of Khalajs is the same language as Argu language in theDīwān Lughāt al-Turk.^[1]

Some of the linguistic reasons demonstrate that Khalaj is a descendant of Arghu:^[2]

1. TheOld Turkic-ny(-) sound is preserved as-n(-) in both Arghu and Khalaj.
2. There is labialization in both. (E.g. bardum, käldüminstead of bardïm, keldim)
3. According to Al-Kashgarî, Argu tribes use the word 'dag' to mean 'not'. The only Turkic language that uses the word 'dag' to mean 'not' today is Khalaj. Oghuzs use the words from *degül, and others *ermeŕ.
4. Arghu hasδ instead ofz. This is also seen in Khalaj.

Mahmud Al-Kashgarî also mentioned the Khalaj (Karakhanid:خَلَج) in hisDivan, but he did not record them as Argu. In theTurkmen article, it is recorded that Khalajs are Turkmen but that they do not consider themselves such. "The Turkmens are actually twenty-four tribes, but the Khalajs, which are made up of two tribes, are not considered Oghuz themselves, as they are sometimes separated from them[.]"^[6] Argu tribes lived inTalas,Balasagun andSayram regions. They were adjacent to the Turkmen. According to al-Kashgari, the Turkmen and Argu were influenced by each other's languages.^[5]

The name Khalaj was recorded by Arab geographers around theSyr Darya inAfghanistan in the 9-10th centuries. Their winter quarters remained in theTalas Region. This is the area where the Argu were located in the 11th century.Al-Khwarizmi, along with Kancina, shows the Khalaj as the remaining tribes from theHephthalites. The Khalaj must have migrated to Iran later. Their homeland, where they were first recorded, is southCentral Asia.^[1]

• Turkic languages

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