“Voice,” “diathesis,” and “genus verbi” are terms that have been employed in very different ways, particularly in approaches to the lexicon and (morpho)syntactic interface of Slavic languages. Theoretical assumptions concerning grammar and lexicon (first of all, notions about lexical units, grammatical categories, inflection, and the role played by morphology) have varied widely. The article supplies a survey of the central notions, and of the frameworks behind them, which since the 19th century have influenced the assessment of voice phenomena in Slavic languages. The most well-founded approaches by Melˈčuk and the Leningrad/St. Petersburg Typology School introduced a clear distinction between voice and diathesis. On the one hand, these approaches have framed grammaticography in many Slavic-speaking countries and influenced Slavists in European and American linguistics; on the other hand, this distinction has often not been followed consistently. The present survey serves to disentangle the inconsistencies.
Inflectional systems can be regarded as paradigms, that is, abstract systems of intersecting grammatical properties (features), as sets of morphophonological word forms, and as members of a lexeme. Purely inflectional systems are compared with voice alternations, transpositions, and evaluative morphology. Affixal inflection is compared with periphrasis and clitic constructions. Careful and explicit description is needed to draw the boundaries between inflectional systems and other types of lexical relatedness. Traditional descriptions are sometimes misleading.