Over the centuries, however, they had become predominantly German-speaking through the processes of German eastward settlement (Ostsiedlung), political expansion (Drang nach Osten), as well as language shift due to assimilation (see also: Germanisation) of local Polish, Slavic and Baltic Prussian population.[2] Therefore, aside from certain regions such as West Upper Silesia, Warmia and Masuria, as of 1945 most of these territories did not contain sizeable Polish-speaking communities.