Rouran language

Rouran (Chinese: 柔然), also called Ruanruan, Ruan-ruan or Juan-juan (Chinese: 蠕蠕), is an unclassified extinct language of Mongolia and northern China, spoken in the Rouran Khaganate from the 4th to the 6th centuries AD, considered a likely early precursor to Mongolic.

Peter A. Boodberg claimed in 1935 that the Rouran language was Mongolic by analysing Chinese transcriptions of Rouran names. Atwood (2013) notes that Rourans calqued the Sogdian word pūr "son" into their language as *k’obun (Chinese transliteration: 去汾 MC *kʰɨʌ^H-bɨun > Mandarin qùfén); which, according to Atwood, is cognate with Middle Mongol kö'ün "son". Alexander Vovin noted that Old Turkic had borrowed some words from an unknown non-Altaic language that might have been Rouran, arguing that if so, the language would be non-Altaic, unrelated to its neighbours and possibly a language isolate, though evidence was scant. In 2019, with the emergence of new evidence through the analysis of the Brāhmī Bugut and Khüis Tolgoi, Vovin changed his view, suggesting Rouran was, in fact, a Mongolic language, close but not identical to Middle Mongolian. Pamela Kyle Crossley (2019) wrote that the Rouran language itself has remained a puzzle, and leading linguists consider it a possible isolate.