The West Slavic languages are a subdivision of the Slavic language group. They include Polish, Czech, Slovak, Kashubian, Upper Sorbian and Lower Sorbian. The languages have traditionally been spoken across a mostly continuous region encompassing the Czech Republic, Slovakia, Poland, the westernmost regions of Ukraine and Belarus, and a bit of eastern Lithuania. In addition, there are several language islands such as the Sorbian areas in Lusatia in Germany, and Slovak areas in Hungary and elsewhere.

The Slavic languages, also known as the Slavonic languages, are Indo-European languages spoken primarily by the Slavic peoples and their descendants. They are thought to descend from a proto-language called Proto-Slavic, spoken during the Early Middle Ages, which in turn is thought to have descended from the earlier Proto-Balto-Slavic language, linking the Slavic languages to the Baltic languages in a Balto-Slavic group within the Indo-European family.