Nikolai Trubetzkoy

Nikolai Trubetzkoy was a Russian linguist and a founding figure of the Prague School of structural linguistics, best known for establishing phonology as a discipline distinct from phonetics. Where phonetics studies the physical sounds of speech, Trubetzkoy argued that phonology should study how a language organizes those sounds into a system of meaningfully contrasting units, or phonemes, and he developed a systematic method for describing phonemes in terms of the specific contrastive features that distinguish them from one another, an approach now called distinctive feature theory. His major work, Grundzuge der Phonologie, Principles of Phonology, was largely complete at the time of his death in 1938 and was published posthumously in 1939, becoming a foundational text that shaped the development of phonology as a field for decades afterward. Trubetzkoy taught for much of his career at the University of Vienna, and alongside his linguistic work he was also active as a historian of Eurasian civilization, though his lasting influence on the history of science rests on his structural approach to sound systems developed within the Prague Linguistic Circle.