Marrism refers to the "New Science of Language" developed in the 1920s by Georgian linguist Nikolai Marr. The "New Science of Language" was a stadial theory according to which class societies speak languages of a different structure than the primordial classless societies proposed by Marxist theory. The languages of primordial societies would be agglutinating and ergative, those of class societies fusional and accusative. Marr rejected the notion of a language family and explained the Indo-European languages as a stage of language development characteristic of class societies rather than a family, while the Japhetic languages were surviving languages of societies that had been classless until recently.
This framework of linguistic theory was endorsed by Joseph Stalin and became a dogma in the Soviet Union which made work on historical linguistics mortally perilous and threw back Soviet linguistics many decades. Even after the Marrist dogma was officially renounced in 1950, stadialist thinking continued to influence many linguists in the Soviet Union, as exemplified in the views of Georgiy Klimov on the development of morphosyntactic alignment.