The article presents in a diachronic and synchronic perspective a minority language (regional) which has existed for centuries in the borderland of cultures and languages - the ethnolect of Kashubians, indigenous, Slavic people living in Gdansk Pomerania - and the history of its contacts with German (unrelated language) and Polish (an example of a Slavic-Slavic borderland); in case of its contact with, foremost, the official version of the German language there was a language conflict. There exists a language continuum between the Kashubian language and the Polish dialects from Masovia and Wielkopolska. They coexisted and complemented each other functionally for a long time.