Chechens
In 1989, 73.4% spoke Russian, though this figure has declined due to the wars for a large number of reasons (including the lack of proper education, the refusal to learn the language, and the mass dispersal of the Chechen diaspora due to the war). Chechens in the diaspora often speak the language of the country they live in (English, German, Arabic, Polish, Georgian, etc.).
Pecheneg language
Pecheneg is an extinct Turkic language spoken by the Pechenegs in Eastern Europe (parts of Southern Ukraine, southern Russia, Moldova, Romania and Hungary) in the 7th–12th centuries. It is also possible that the language was spoken by the Cumans, per Byzantine princess Anna Komnene.