@avahez they are singing in Tajik (a dialect of Persian). Tajik is the main language of the Bukharian Jews of Central Asia, as seen here. The Tajik spoken by them is a bit different from normal Tajik due to its inclusion of Hebrew words. But generally the languages are almost identical. Especially the literary language used in songs and poetry as seen here. The colloquial dialects differ depending on the region of central asia.
