According to RI1.7B2, when an item is in a non-Slavic language of Central Asia written in the Cyrillic alphabet, record the language in a note.

100 1 Jahangirov, Muradkhan.
245 10 Milli tashakkul marhalasinda azarbaijan adabi dilinin aparyjy uslublary :‡bmonografiiasynyn /‡cMuradkhan Jahangirov.
260 Baky :‡bElm,‡c1989-
...
500 In Azerbaijani.

See also:
Artistic Form for Non-Slavic Cyrillic Languages