käänetevahetuse

Käänetevahetus is a term used in Estonian linguistics to describe a process in multilingual contact in which inflectional morphology, particularly case endings, is exchanged or redistributed between languages. The term combines käänete (inflection/case) and vahetus (exchange). It covers changes that arise from social and linguistic contact and affect how grammatical relations are encoded, including borrowing of endings, diffusion of analytic strategies such as the use of prepositions instead of cases, or reanalysis of existing morphemes.

Mechanisms include borrowing of morphemes attached to nouns or adjectives, enabling new case endings to appear; grammaticalization or reanalysis, where synthetic case endings give way to prepositional constructions or vice versa; and leveling or diffusion, where one language's case system influences another's, especially in bilingual communities, schools, or media environments.

The phenomenon is discussed in relation to other language-contact processes such as calquing, morphological borrowing, and grammaticalization. Researchers note that käänetevahetus can lead to convergence or divergence of case systems depending on usage, prestige, and language ecology. Data for study come from typological comparisons, corpora, and historical records.

See also: language contact, morphological borrowing, grammaticalization, calque.