Polonization
According to the Polish national census of 1921, there were around 1 million Belarusians in the country. There are historians, however, who estimate the number of Belarusians in Poland at that time to be 1.7 million or even up to 2 million. In the 1921-1926 period Poland did not have a consistent policy towards its ethnic minorities. Belarusians in Western Belarus faced Polonization. Belarusian schools, not being subsidised by the Polish government, were facing severe financial problems by 1921.
After the 1930 elections in Poland, Belarusian representation in the Polish parliament was reduced and in the early 1930s the Polish government started to introduce policies intended to Polonize minorities. Use of the Belarusian language was discouraged. Not a single Belarusian school survived by the spring of 1939, and only 44 schools teaching the Belarusian language still existed in Poland at the beginning of World War II.
Refugees from Western Belarus were arrested by Soviet authorities and frequently executed, Kurapaty graves contain many products from Poland - cloths, shoes. The most prominent victim of NKVD was the activist and linguist Branislaw Tarashkyevich. Frantsishak Alyakhnovich was liberated in 1933 after several years in Soviet camps and exchanged toward Tarashkyevich.
Read more about this topic: West Belarus