baltkrievisks

Etymology
From.

Adjective

 * 1) Belarusian relating to the Belarusian language; relating to Belarusians or to Belarus

Usage notes
English “Belarusian” as an attributive adjective usually corresponds in Latvian to, the genitive plural form of. The adjective is commonly used as a predicate (“this is Belarusian”), or in its adverbial form.