For most of his life Baudouin de Courtenay worked at Imperial Russian universities. In 1919-1929 he was a professor at the re-established University of Warsaw in a once again independent Poland.
He was born in Radzymin, in the Warsaw Governorate of Congress Poland (a state in personal union with Russian Empire), to a family of distant French extraction. One of his ancestors had been a French aristocrat who migrated to Poland during the reign of Polish King August II the Strong. In 1862 Baudouin de Courtenay entered the "Main School," a predecessor of the University of Warsaw. In 1866 he graduated from its historical and philological faculty and won a scholarship of the Russian Imperial Ministry of Education. Having left Poland, he studied at various foreign universities, including those of Prague, Jena and Berlin. In 1870 he received a doctorate from the University of Leipzig for his Polish-language dissertation On the Old Polish Language Prior to the 14th Century.
Baudouin de Courtenay established the Kazan school of linguistics in the mid-1870s and served as professor at the local university from 1875. Later he was chosen as the head of linguistics faculty at the University of Dorpat (now Tartu, Estonia) (1883–1893). Between 1894 and 1898 he occupied the same post at the Jagiellonian University in Kraków only to be appointed to St. Petersburg, where he continued to refine his theory of phonetic alternations. After Poland regained independence in 1918, he returned to Warsaw, where he formed the core of the linguistics faculty of the University of Warsaw. From 1887 he held a permanent seat in the Polish Academy of Skills and from 1897 he was a member of the Petersburg Academy of Sciences. In 1925 he was one of the co-founders of the Polish Linguistic Society.
His work had a major impact on 20th-century linguistic theory, and it served as a foundation for several schools of phonology. He was an early champion of synchronic linguistics, the study of contemporary spoken languages, which he developed contemporaneously with the structuralist linguistic theory of Swiss linguist Ferdinand de Saussure. Among the most notable of his achievements is the distinction between statics and dynamics of languages and between a language (an abstract group of elements) and speech (its implementation by individuals) – compare Saussure's concepts of langue and parole. Together with his students, Mikołaj Kruszewski and Lev Shcherba, Baudouin de Courtenay also shaped the modern usage of the term phoneme (Baudouin de Courtenay 1876–77 and Baudouin de Courtenay 1894), which had been coined in 1873 by the French linguist A. Dufriche-Desgenettes who proposed it as a one-word equivalent for the German Sprachlaut. His work on the theory of phonetic alternations may have had an influence on the work of Ferdinand de Saussure according to E. F. K. Koerner.
Three major schools of 20th-century phonology arose directly from his distinction between physiophonetic (phonological) and psychophonetic (morphophonological) alternations: the Leningrad school of phonology, the Moscow school of phonology, and the Prague school of phonology. All three schools developed different positions on the nature of Baudouin's alternational dichotomy. The Prague School was best known outside the field of Slavic linguistics. Throughout his life he published hundreds of scientific works in Polish, Russian, Czech, Slovenian, Italian, French and German.
Apart from his scientific work, Baudouin de Courtenay was also a strong supporter of national revival of various national minority and ethnic groups. In 1915 he was arrested by the Okhrana, Russian secret service, for publishing a brochure on the autonomy of peoples under Russian rule. He spent 3 months in prison, but was released. In 1922, without his knowledge, he was proposed by the national minorities of Poland as a presidential candidate, but was defeated in the third round of voting in the Polish parliament and eventually Gabriel Narutowicz was chosen. He was also an active Esperantist and president of the Polish Esperanto Association.
In 1927 he formally withdrew from the Roman Catholic Church without joining any other religious denomination. He died in Warsaw. He is buried at the Protestant Reformed Cemetery in Warsaw with an epitaph: “He sought truth and justice.”
His daughter, Cezaria Baudouin de Courtenay Ehrenkreutz Jędrzejewiczowa was one of the founders of the Polish school of ethnology and anthropology as well as a professor at the universities of Wilno and Warsaw. He appears as a character in Joseph Skibell's 2010 novel, A Curable Romantic.
Baudouin de Courtenay was the editor of the 3rd (1903–1909) and 4th (1912–1914) editions of the Explanatory Dictionary of the Live Great Russian language complied by Russian lexicographer Vladimir Dahl (1801–1872).
Contemporaries noted his early maturity as a scientist. Encyclopedic dictionary of Brockhaus and Efron in the volume, published in 1891, calls the 46-year-old Baudouin de Courtenay "one of the most prominent contemporary linguists". Baudouin himself was an unusually humble man. About himself he wrote that he "was distinguished unsatisfactory by scientific training and little knowledge".
Baudouin de Courtenay made a revolution in the science of language: to it in linguistics historical approach prevailed — the languages were studied only by the written records. He is in his work proved that the essence of language in speech activity, and therefore, it is necessary to study living languages and dialects. The only way to understand the mechanism of functioning of language and to verify the correctness of linguistic theories.
Baudouin de Courtenay for many years studied the different Indo-European languages, wrote his scientific papers not only in Russian and Polish, but also German, French, Czech, Italian, Lithuanian and other languages. Working in the expeditions that studied the Slavic languages and dialects, he recorded their phonetic features. His discoveries in the field of comparative (typological) analysis of Slavic languages anticipated the emergence of ideas that later found their reflection in the works of the eminent typologist-Slavist Roman Jakobson. These studies allowed the Baudouin de Courtenay (including the ideas of early died younger colleagues, talented N. V. Grushevskogo — also a pole, who worked in Kazan) to create a theory of phonemes and phonetic alternations. The theory set forth in his "essay of phonetic alternations" (1895). Its logical continuation was created by a scientist theory letters. Thus, Baudouin became a founder of phonology, a precursor of the theory of Nikolai Trubetskoy.
Baudouin de Courtenay was the first to be applied in linguistics the mathematical model. Proved that the language development can be affected, not just passively record all developments. On the basis of his work a new direction — experimental phonetics.
In the study of language-Baudouin de Courtenay was not confined within linguistics. On the contrary, he believed that linguistics should be based on the achievements of psychology and sociology that a complete study of linguistic factors is impossible without referring to the data of Ethnography, cultural history, archeology and other Sciences. All this scientist is not only declared but also exercised in his works.
He prepared the third and fourth edition of the dictionary Dahl, adding the etymology, correcting the separation of nests (Dahl often arbitrary), as well as replenish it with new words, including making absent Dahl vulgar-brane language. Their additions were heavily criticized in Soviet times, "Bodunovsky the dictionary Dahl" not reprinted. Reprints of Soviet times are based on the original text of the second edition of the dictionary Dahl; version Baudouin usually considered to be a dictionary.
Baudouin de Courtenay was actively interested in artificial languages, repeatedly supporter of Esperanto. In October 1907, he participated with Otto Espersen and other scientists in the international delegation for the adoption of an international auxiliary language (FR. Délégation pour l'adoption d'une Langue Auxiliaire Internationale) as its Vice-Chairman. Was personally acquainted with Louis Zamenhof, founder of Esperanto, but an Esperantist did not consider themselves.
Working in Kazan in the years 1874-1883, the scientist founded the Kazan linguistic school, in which bloomed the talent of the greatest scientist Vasily Bogoroditsky, in St. Petersburg, he created the St. Petersburg linguistic school, which under his direct influence the formation of the great Russian linguists of the twentieth century Lev Scherba and Yevgeny Polivanov. Baudouin de Courtenay many, especially in Russia, is considered one of the founders of structuralism, along with Ferdinand de Saussure. The influence of the St. Petersburg school, especially of its founder, it was very noticeable in Russia and the USSR, and in Poland and Czechoslovakia. She extended a number of provisions, particularly in the area of phonology, with the help of their promotion of the Prague linguistic circle became a cornerstone in the world of science.
Some of the works of Baudouin de Courtenay was published in Voronezh magazine "Philological notes".