Prostaya mova

Prostaya mova (mowa prosta, prosty jazyk; Belarusian: простая мова, literally "simple language" or "simple speech") is a colloquial term used to denote the regional varieties of the Belarusian language (often mixed with Polish, Russian, and Lithuanian elements) spoken in the borderlands of Lithuania, Belarus, and Poland. It is primarily spoken in the Vilnius Region (Lithuania), Hrodna Region (Belarus), and the Podlaskie Voivodeship (Poland) (specifically in the Sokółka County).

Speakers of prostaya mova often identify themselves as Poles (especially in the Vilnius Region) or Belarusians, but refer to their native language as "simple" to distinguish it from standard literary languages (Polish, Russian, Lithuanian, or standard Belarusian).