Polish linguist and slavist
According to Wikipedia,
Jan Niecisław Ignacy Baudouin de Courtenay was a Polish linguist and Slavist, best known for his theory of the phoneme and phonetic alternations. For most of his life Baudouin de Courtenay worked at Imperial Russian universities: Kazan , Dorpat , Kraków in Austria-Hungary, and St. Petersburg . In 1919–1929 he was a professor at the re-established University of Warsaw in a once again independent Poland.
Jan Baudouin de Courtenay is affiliated with the following schools: